HydroBuddy v1.80 : The First Free Open Source Hydroponic Nutrient Calculator Program Available Online

HydroBuddy is a completely free and open source program for the calculation of nutrient solutions for hydroponics and general agriculture built by me – Daniel Fernandez – based on my experience in hydroponics as a professional chemist. This piece of software was coded from the ground up using the Lazarus open source programming suite and implemented using appropriate database solutions as well as a  powerful linear equation solving algorithms from AlgLib. HydroBuddy is available for Linux and Windows. HydroBuddy is released under the GPL license. For Linux or Windows installers are included. You can also use on MacOSX if you compile from source.

Screenshot of the “Main page” tab of the HydroBuddy hydroponic fertilizer calculator

These are some of HydroBuddy’s features :

  • Calculates the weights of specific substances needed to arrive at specified concentrations of different elements (formulation to salt weights calculation)
  • Easily fine tune your salt weights after calculations.
  • Contains library with commonly available fertilizer salts (new in v1.7)
  • Raw salts in the included DB have links to help new users know where to buy them (accessible by clicking the salt name in the results tab). Please note these are amazon affiliate links that support the development of the software. (new in v1.7)
  • Includes ability to save and load lists of substances used for calculations. (new in v1.7)
  • Empirical model for the prediction of EC (new in v1.8)(read more here)
  • Calculations in ppm, mmol/L, mol/L and meq/L.
  • Calculate liquid additions in mL and add any custom substances as liquids
  • Edit the percentage elemental composition of each substance or add new ones to fit your needs
  • Powerful open source linear equation solver provided by AlgLib
  • Always tries to find the best mathematical fit to a formulation by a given group of substances
  • Allows to get the concentration values for the addition of a certain specified amount of substances (salt weights to formulation calculation)
  • Easy-to-use interface for the addition, edition and assignation of substances to calculations
  • EC prediction module based on an empirical mathematical modification of a calculation based on limiting molar conductivities
  • Use the resulting weights of a formulation calculation to perform a calculation of the opposite nature and vice versa (easily allows you to see the effect of manual modifications)
  • Calculations for both direct additions and A+B concentrated solutions
  • Use any custom substance as a part of an A+B concentrated solution calculation
  • “Copy Commercial Nutrient” module which allows you to copy the ppm results of a commercial nutrient formulation
  • Water quality module allows you to include water quality analysis within the calculations
  • Adequate implementations of instrumental and gross errors with custom instrument precision input
  • Proper database implementation allows you to easily save your custom formulations
  • Set default water quality and data log data sets that load automatically on program startup
  • Save and load formulations using any concentration unit.
  • Choose between grams or ounces
  • Choose between liters, gallons and cubic meters for volume inputs
  • Export calculation results to a CSV file
  • Tutorial tabs showing and explaining the main features of the program !

The program allows anyone to easily carry out calculations for the preparation of nutrient solutions, a very cumbersome task that can take a lot of time and effort when done manually. If you’re having trouble with HydroBuddy and you would like to purchase support please email me by using the contact form with your requirements to receive a quote. If you are using HydroBuddy for academic purposes please cite its use as follows:

Daniel Fernandez, “HydroBuddy: An open source nutrient calculator for hydroponics and General agriculture”, v1.8, url: http://scienceinhydroponics.com , 2020   You can download the program through the following links:

Just unzip the program and run the hydrobuddy.exe file.
Unzip, then make sure you execute “chmod +x hydrobuddy” within the folder so that you can execute the program.

Note for MacOS users:  MacOS won’t allow you to open Hydrobuddy correctly unless you compile it yourself. To do this you’ll need to build HydroBuddy on your own MacOS computer. Install the Lazarus IDE and then compile the HydroBuddy project from source. Please note that the software is provided “as is” (no support available for free). If you want to get a support quote please contact me via the website’s contact form.

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  • Ramesh
    June 9, 2010 @ 1:16 pm

    Hi Daniel,

    This is really a great work and it give complete flexibility to the user. I really appreciate and was looking for some thing like this. I just noticed one problem, when i open in my Window PC (resolution is 1440 by 900 pixels), i am not able to see the full screen of the calculator, below Manganese sulfate and zinc sulfate.


    • Leon
      April 24, 2012 @ 7:09 am

      I installed this program and started inputting my fertilizer. after the 3ed input this calculator crashed. I’m running windows 7. Please help???????

    • Rajat
      June 5, 2020 @ 3:01 am

      Hello Ramesh, was going through the questionnaires which people have asked. Have few doubts while doing some calculations in Hydrobuddy. Need some guidance. Would you be willing to spare some time and guide me on the same? Would really appreciate it. Thanks!

  • Daniel
    June 9, 2010 @ 2:34 pm

    Hello Ramesh,

    Thank you very much for your comment :o) Indeed, some people have also pointed out this problem and I will definitely have it fixed for the next version release. In the meantime you can use the calculator by temporarily changing your resolution to 1280×1024, it may look a little bit stretched but it will allow you to use it to its full extent. Thank you very much for your comment and interest !

    I hope you enjoy the app a lot ,

    Best Regards,


    • William
      June 21, 2013 @ 3:40 pm

      Hello Daniel,
      I would like to seek your advice on some problems I encountered while using the nutrient calculator.
      When I was trying to create a new solution on the database, the calculator required me to enter the different type of compositions in percentages. However when I try to copy a formula from the WSDA website, the composition of the fertilizers are given in ppm AND percentages.. How can I convert to make them all the same to suit the calculator? And is there explanation for the column at the side which says “…volume” and “W/W%” ?
      Thank you so much!

      • admin
        June 23, 2013 @ 3:21 pm

        Hi William,

        Thank you for your post :o) HydroBuddy is provided without any support. To get an answer to your question please donate 10 USD to HydroBuddy by using the paypal link on the program, this helps me continue the development of the software. Thanks again for posting,

        Best Regards,


        • luigi
          June 10, 2020 @ 12:19 pm

          hi, can you add the possibility of entering the water data in mmol/l instead of ppm?

          • Doug
            August 18, 2020 @ 5:57 pm

            You can easily do this math yourself one time and then keep some reference numbers around.
            1) Determine molar mass of your additive
            2) Divide by 1000 – this is the weight of one millimole
            3) Convert the volume you have of your solution on hand to liters and multiply that number by the molarity of the solution – this is how many moles you have
            4) Take the millimolar mass from step 2 and multiply by the number of moles in your solution – this is your total mass
            5) Take the total mass from step 4, expressed in milligrams, and divide over your total volume, expressed in liters – this is your PPM

  • K Novak
    June 9, 2010 @ 8:36 pm

    Nice one! I was very surprised this morning, when I saw your calculator! You just mentioned yesterday it will come :)

    Anyway, I have the same problem as Ramesh, my laptop has the resolutin 1366×768, and I cannot see the bottom of the window. A scrollbar can solve the problem!

    Congratulation Daniel!

  • Daniel
    June 10, 2010 @ 4:15 am

    Hello Novak,

    Thank you very much for your congratulations :o) I am glad you like the software. Obviously a scrollbar could fix this issue but I am doing a few additional implementations so I will release an update with this fix and some new features once I am done :o). You can simply change your resolution to 1280×1024 to use it in the meantime (or use a different computer?). Thank you very much again for your comment ! I hope you find the calculator useful,

    Best Regards,


  • Daniel
    June 10, 2010 @ 4:12 pm

    Hello Everyone,

    The calculator has just been updated to version 0.2 :o) Here are the fixes and additions you will find :

    – Fixed Resolution Problem

    – Changed to tabbed interface for easier use and easier addition of future features (very easy to add new tabs :o))

    – Added Ammonium Molybdates (ortomolybdate and heptamolybdate) to salts list

    – Added the ability to save and load formulations through a drop down menu. All ppm nutrient levels and solution volumes are saved with the name you input. You can then load them simply by selecting them from the menu. If you close the program simply click the "load formulations" button to get them back. You can also remove them using the "remove selected" button.

    -You can also add external formulations, simply place the file of the formulation in the folder where the program is located in, input the name next to the "add external" button, click it and the formulations should appear in the drop down menu. You can save your formulations and share the files with anyone you want :o) files for formulations are saved within the same folder as the program.

    Well, I hope that all these changes make the calculator much more useful and user-friendly for everyone out there. Hopefully it will also enable us to easily share a lot of formulations :o). I am also implementing other features including the "reverse" (input salts, fertilizer, etc, -> get ppm) and a pH and EC prediction module.

    Thank you very much for all your comments and support :o) Please let me know what you think !

    Best Regards,


  • Ramesh
    June 11, 2010 @ 6:41 am

    Hi Daniel,

    This enhancement is very good and user friendly.

    I have a question.

    1. when we get an error for a particular component. For example in example_recipe.txt, we have error of -35.45% for Ca. How do we handle this.


  • Daniel
    June 11, 2010 @ 12:18 pm

    Hi Raurs,

    Thank you for your comment :o) I am glad you find the implementation user friendly !

    The error situation can be handled in different ways depending on whether or not you find the error acceptable. For example on the default recipe you might find a 35% excess of calcium (with the total being around 270ppm) too high so you might consider reducing both calcium and nitrogen (Nitrate) requirements of your formulation to have a more balanced solution.

    Of course in order to calculate the formulations one or two elements must contain errors to have some degrees of freedom for calculation, the nature of these errors is often small or due to the actual makeup of the formulation and the salts used.

    The next version will be released with a bunch of standard formulations so that people will get a better idea of what solution they need and which one best fits their salta availability.

    Thank you very much again for your comment :o) Please leave any additional feedback you may have,

    Best Regards,


  • Srikanth
    June 14, 2010 @ 11:46 am

    Hi Daniel,

    Thank you for this super tool. I am restarting my Hydroponics for the year now that the harsh Summer in India is over.

    I have one suggestion. Can you include a purity of salt as one of the input values (default 100%)? The reason is here in India getting quality salts is difficult and very expensive.


  • Daniel
    June 14, 2010 @ 1:43 pm

    Hi Srikanth,

    Thank you very much for your comment :o) I am glad you like this free tool I have made.

    Certainly, I will add a purity feature when I release the next version of the calculator,

    Best Regards,


  • Leslie
    June 14, 2010 @ 6:38 pm

    Awesome tool. Now I can finally look into mixing my own nutrients. Looking forward to the next release.

  • Srikanth
    June 15, 2010 @ 2:56 am

    Hi Daniel,

    Couple of bugs to report, I guess.

    1) I need 0 S. When I enter 0 and click the "Calculate Formula" button, I get the error "Floating point division by zero.".

    2) If I leave the value of S empty and click the "Calculate Formula" button, I get the error
    '" is not a valid floating point value.".

    Can you please look into this as well.


  • Daniel
    June 15, 2010 @ 11:33 am

    Hi Srinkanth,

    Thank you for your comment and bug reporting :o) The fact is that the program will not accept 0 for anything except N as ammonium due to the fact that everything else is necessary to achieve a formulation useful in hydroponics.

    If you don't want to use S, just set S to a very low value (like 0.01) and the program will just warn you if you don't have any S containing salts but the end results will have an S value of 0. I will fix this for the next release. Thanks again for your suggestion,

    Best Regards,


  • Daniel
    June 16, 2010 @ 4:46 pm

    Hello Everyone,

    After a lot of hard work I am glad to announce the next version of this free hydroponic nutrient calculator which from now on will be called "hydroponic buddy". I made the following improvements/fixes/additions :

    – Added Custom Salt/Fertilizer (you can now add any salt or fertilizer you want with a custom composition)

    – Added Purity Feature (salt purity can now be specified)

    – Added "salt to formulation" feature, you can now input a given mass of salt in grams and a given volume and get the final ppm concentration. This is very useful if you want to examine a fertilizer you are currently using or just do manual modification to the automatically calculated formulas

    -Custom salts/fertilizers can also be used in conjunction with other salts/fertilizers when calculating nutrient solutions through the "direct addition" method. Using the other method this cannot be done because compatibility issues cannot be addressed knowing only percentage compositions.

    – Added concentrated A+B type solution preparation. The program now has a "preparation mode" where weights and instructions are given to prepare A and B stock solutions which are then used to prepare the final reservoir.

    -Program automatically checks salt compatibility of salts in A+B solutions, it will warn you if you are attempting to use incompatible salts.

    -Problem with zero divide errors when nutrient levels are set at 0 has now been fixed.

    -Problem related with inaccurate calculation when using gallons has always been fixed.

    You can download the latest version using the link provided on this post :o) I hope you enjoy it a lot ! Make sure you leave any comments, suggestions or bugs you may find,

    Best Regards,


    • June 16, 2016 @ 2:05 am

      Can this calculator be used to analyze production, and strengths of organic nutrient? If not, being a professional chemist, can you lead me in the right direction concerning the low cost production of viable, effective organic nutrients. Especially an effective non salt base cal/mag nutrient. Thanks for your time.

  • Daniel
    June 17, 2010 @ 5:18 pm

    Small fixes/additions :

    -Fixed a small problem where the custom salt addition form had Mn and Zn interchanged. Mn and Zn now match.

    -I forgot to mention I added a pH and EC module. These predictions only work with the default salt as the ionic nature of custom salts is not known by the program.

    Please leave any comments !

    Best Regards,


  • Daniel
    June 26, 2010 @ 5:47 pm

    Fixed a nasty bug that caused some very erroneous A+B calculations when certain salt combinations were used. The latest version with this fix has been uploaded and A+B calculations now work well. Please update your calculator or you won't be able to perform adequate A+B calculations !


  • Daniel
    June 27, 2010 @ 10:50 pm

    Hello Everyone,

    I am glad to announce the release of version 0.7 of my hydroponic calculator (hydroponic buddy). The new version features many improvements over 0.5 which are detailed below (thank you for all the suggestions by the way !) :

    – added option to change from grams to ounces
    – added EC prediction for custom salts and for salt to formulation calculations
    – added option to save selections of salts ( only works for included salts)
    – added Yara brand calcium nitrate
    – added option to prepare custom amount of stock solution (for A+B calculations)
    – added cubic meters for stock solution calculations
    – highlighted stock solution volumes in RED in the results page to make sure the user sees them when doing A+B calculations

    – New section called Nutrient Log !!!
    – Log your pH and EC levels as a function of time
    – Plot charts
    – analyze your results
    – the analyzer also gives you some observations if it notes a lot of deviation or variation on your EC/pH levels.
    -the analyzer also tells you when to change your reservoir or top off with water !
    – You can also use the nutrient log for run to waste systems using the checkbox included
    – analyze the average/highest/lowest difference between in and out pH/EC levels (for run to waste systems).
    – Save data for future reference.

    Please leave any comments, observations or suggestions you may have regarding the current version :o) Thank you very much again for your interest and for helping me make my software better !

    Best Regards,


  • Daniel
    July 1, 2010 @ 6:05 pm

    Hello Everyone,

    Today I have done a minor update to version 0.72. These are the changes :

    – Added a checkbox to automatically place calculation weight results into the mass fields on the "Nutrient Salts Used" tab, this will make the tweaking of initially calculated values a lot easier. It will also allow you to confirm the formulation you will be finally getting.

    – Added Current time button on the nutrient log. This will allow you to get the current time automatically without having to input it manually

    – Added a Day to Day checkbox on the nutrient log which allows you to enter values of pH and EC without entering dates (the program assumes a one day separation between data logs).

    – Made some minor graphical changes to the nutrient log section

    – Automatically check for software updates feature :o) !! With this feature you will be able to easily check within the calculator if you have or don't have the latest version.

    I hope to introduce a lot of additional content before version 1.0 comes out. Right now I am working on some additive features and the addition of about 20 more salts to the default list within the program. Thank you very much again for all your help and suggestions :o)

    I would love to know how you are using the calculator and how I can make it better for you ! Stay tuned for more tutorials on my blog :o)

    Best Regards,


  • Daniel
    August 11, 2010 @ 3:11 am

    Hello Everyone,

    Good news today :o) Version 0.8 of the calculator is finally out and with it I have made several important fixes and additions.

    These are the changes for this version :

    – Added a tutorial button on the "welcome page" which contains links to all relevant tutorials within my blog.

    – Added Si, Na and Cl. All of these elements are now tracked and their conductivity contributions are measured. However Cl is not included as a "recipe element" since additions of chloride ions are never necessary due to the fact that almost all water sources contain it within the necessary ranges for plant growth (chlorides are also widely present as salt impurities). However the calculator will tell you the contributions of Cl in ppm of salts within the bottom left corner box on the results' page.

    – Added 28 new default salts, acids and bases including potassium and sodium silicates, sodium nitrate, zinc sulfate monohydrate, nitric acid, sulfuric acid, ammonium sulfate, potassium chloride, magnesium chloride, some carbonates, many complexes, many transition metal nitrates, potassium hydroxide, etc.

    -Implemented new windowed settings for the preparation modes (direct addition and concentrated A+B)

    – The default preparation mode now allows you to choose between "direct addition + Fe and micro concentrated solutions" or "adding all salts directly". This is useful if you have high precision scales or if your reservoir size allows you to weight everything directly with enough precision without having to prepare concentrated solutions.

    – Changed EC prediction mode implementation to an empirical model I came up with that gives results closer to reality.

    – Introduced "water quality" input with the ability to save and load different water quality settings. These measurements are used when your formulation is calculated to adapt your formulation against your particular water type.

    – I also removed the pH prediction module because the simplifications it was based on are no longer valid with such a wide array of acids and bases. Sadly implementing a precise pH prediction method requires the solution of complex mathematical systems (if phosphates and carbonates are used it requires the solution of a system of about 8-12 non-linear equations) which my calculator is not capable of doing. I tried to use the freely available Maxima libraries but failed to implement a reliable solution. However I believe this feature is not that necessary and probably not worth all the trouble.

    Hopefully this new calculator version will be useful to those of you who haven't been able to use the calculator due to its previously smaller salt database and lack of a water quality feature.

    I hope you enjoy this new release a lot ! :o) Please send me any suggestions or observations that will help me make the software better.

    Thank you very much again for all your interest :o)

    Best Regards,


  • Srikanth
    August 11, 2010 @ 3:15 am

    Thank you very much for your continued effort and improvements. A big THANK YOU for including the 'Water Quality' feature.


  • Daniel
    August 13, 2010 @ 8:20 pm

    Hello Everyone,

    Thank you very much for your comment Srinkanth. I hope that you find this version very helpful !

    I also wanted to comment that a new version (v0.81) has just been released. This new version includes some fixes related to some of the new transition metal nitrates as well as some problems that caused errors when using the Ounces instead of grams (just for the salts to formulation part).

    Thank you very much for all your interest and support :o)

    Best Regards,


  • Christian
    August 14, 2010 @ 12:42 pm

    Hi Daniel

    I've been continuing to use your program, but one thing that doesn't seem to be working for me, or is not clear how to use, is the "quickload list"
    "add external" current/selected ans "Save results"

    I'm really not sure how these work, I've tried to save some formulations in the past but to no avail. Is there an explanation how to use this anywhere? thanks!

    -hydro follower

  • Daniel
    August 14, 2010 @ 1:36 pm

    Hi Christin,

    Thank you for your comment :o) I will now explain what each one of those features does :

    – Quick Load List : This list includes all formulations (formulations are different from results !!) that have been saved. In order to populate the list with your previously saved formulations you must click the "load formulations button"

    – Add Current : Adds the current formulation (desired ppm values for each element) to the Quick Load list. In the future you will need to click the "load formulations button" to have this formulation available when the program starts.When you use this a file is created within the calculator's folder with the formulation (this file can be shared with other users who can add it with the "add external" button)

    – Add External : Adds an external formulation saved as a file within the same folder as the calculator's executable to the drop down list. In order to recover this later on you will need to populate the quick load list using the "load formulations" button.

    – Save Results : Saves a text file with the name chosen on the Edit box in the same folder as where the calculator's executable is located. This text file includes the RESULTS of the calculation (salts, weights, etc) so that they can be printed and used in an easier fashion when actually preparing the formulations.

    I hope this clears it up :o) Thank you very much again for your comments and interest,

    Best Regards,


  • Daniel
    August 16, 2010 @ 11:24 am

    Hello Everyone,

    Just a small update to v0.82. These are some of the changes :

    – fixed nitrate assignation problem that caused sodium nitrate to be used as main nitrate source despite selecting potassium and calcium nitrates

    – fixed a problem with nitric acid which contributed ammonium instead of nitrate when using the "salt to formulations" tab.

    – added ammonium phosphate to the default salts

    – fixed a few other minor bugs

    I hope you enjoy this small fixes :o)

    Best Regards,


  • Robert
    August 20, 2010 @ 9:05 am

    Hi Daniel,

    thank you very much for your effort and for providing this tool. But there is a small problem on german computer systems. The Germans use a decimal comma "," rather than a decimal point "." to seperate the fractional from the integral part of a number. So, on German systems, the given formulas, even the pre-loaded values on the "Desired Formulation" tab won't work. The program says: "0.01" is not a valid floating point value." Germans have to replace the "." by a "," to make ist work.

  • Daniel
    August 20, 2010 @ 10:58 am

    Hello Robert,

    Thank you for your comment and for pointing out that problem :o) I have just released v0.821 which includes a fix that makes the program use "." as a decimal point even if the system defined decimal separator is ",". This will allow you to run the calculator without any problem regardless of the system. Let me know if it is working correctly for you now :o) Thanks again for your comment,

    Best Regards,


  • Robert
    August 20, 2010 @ 11:22 am

    It' working now, thank you :).

  • Daniel
    August 23, 2010 @ 1:18 am

    Hello Everyone,

    I just wanted to let you know that version 0.85 of hydrobuddy has just been released. This new version includes several important additions :

    – A checkbox has been added to the "Salts to Formulations" tab enabling the automatic copying of the results to the "desired formulations" tab. This will make the calculator easier to use for those using this feature extensively to design their solutions.

    – Instrumental error has now been implemented :o) This feature is very important since it allows you to see the effect of the precision of your volume and weight measuring instruments on your actual concentrations. For example you may get a 5% error for a salt but a +/- 10% error due to your scale's precision meaning that the calculation's error is negligible compared to your instrument's capabilities. These errors will be shown on the results page next to the regular calculation error.

    – A new button to select these instrument precision parameters has just been added to the "desired formulations" tab so that you can select the precision of your scale and volume measuring instrumentation (defaults are +/- 1L for volume and +/- 0.01g for weight).

    – The calculator will also worn you if your scale is too imprecise for the formulation concentrations and volumes you want to prepare. It will tell you the exact element where the problem is found and it will advice you to increase the solution's volume or your scale's precision.

    I hope that you can now enjoy this new features and the additional functionality they bring to the calculator :o). Thank you very much again for all your interest !

    Best Regards,


  • Daniel
    August 23, 2010 @ 12:14 pm

    Hello Everyone,

    I have just released v0.851 to include a small fix dealing with the use of Potassium silicate.


  • Daniel
    September 1, 2010 @ 3:54 pm

    Hello Everyone,

    I have just released v0.852 with some small fixed. Some broken tutorial links have been fixed as well as an error that caused Na and Cl not to be taken into account in the EC estimations when using the "Salts to Formulation" tab. Thank you very much for all your interest and visits !

    Best Regards,


  • Chris
    September 2, 2010 @ 5:28 am

    Hello Daniel,

    Your calculator is easy to use. i had a little problem using ammonium nitrate…i'd change the ammonium ppm, and the salt weight would stay the same.

    i've made a formula NPK 275-101-395, 219 Ca, 84 Mg, Bo 5, Mn 5, Zn 3, Cu 1, Mo 0.09. i use RO water, potassium nitrate, calcium nitrate, iron eddha, magnesium sulphate, potassium phosphate, boric acid, manganese sulphate, zinc sulphate, copper sulphate, and chelated molybdenum. i get precipitate. part a seems to be iron, and part be seems to be potassium and copper. why is this? is the calculator allowing me to add more salts than is soluble?

    Best regards

  • Daniel
    September 2, 2010 @ 10:48 am

    Hello Chris,

    Thank you very much for your comment :o) I will fix this problem with ammonium nitrate with the next release. It seems to be that the calculator attempts to fulfill nitrate and not ammonium requirements with this salt so it does not see that it requires to use it when nitrate requirements are already fulfilled.

    The calculator does not allow you to add more salts than they are soluble and your ppm values show that you are within the solubility limits of all salts at acid pH. However you have to consider that potassium phosphate is a very basic salt, try to add the potassium phosphate first and then adjust the pH to about 4 with an acid, then add the rest of the salts. It is important here to consider pH since many salts to precipitate as pH increases.

    I hope this helps you ! :o)

    Best Regards,


  • Chris
    September 2, 2010 @ 4:21 pm

    Thank you Daniel!

    Will adding phosphoric acid to a prepared stock solution dissolve the precipitate?

    Part A has about 50 ml of precipitate in 1L of stock solution. In what order should I be mixing salts? To what pH do I set the solution?

    I really appreciate your help!

  • Daniel
    September 3, 2010 @ 2:16 am

    Hello Chris,

    Thank you for your email :o) Phosphoric acid is not a good choice since it will add phosphate and solubility may get more complicated. I would add nitric acid instead until the solution clears up (usually setting this concentrated solution to a pH of 3-4 will do the trick). However measure volume additions and take note so that you can calculate your change in N (shouldn't be much).

    Salts should generally be mixed from the least to the most soluble, taking care to make sure salts are fully dissolved before adding the next. It is also important to monitor pH and make sure that it remains acidic, especially if iron is contained within the preparation. Generally if acidic salts are used there are no significant problems, precipitates start to appear – especially in concentrated solutions – when basic salts are used or basic impurities are present (or when people don't use distilled water but tap water with carbonates).

    Tell me how it works out :o) Thanks again for your interest,

    Best Regards,


  • Chris
    September 4, 2010 @ 4:04 am

    i will try nitric acid. thanks! will ppt still dissolve in my reservoir and be ok to use?

    i'm trying to reverse engineer house & garden's aqua flakes. i suspect it uses nitric acid for half of total N. first, isn't nitric acid a liquid? how will i know how much to add? i tried using nitric acid to make up 20 ppm of 127 ppm total N. the calculator came up with 37.4g calcium nitrate, and -19.2g nitric acid!!

    aqua flakes uses 2.75 ml/L to get to 2.0 mS. how are they getting it so concentrated, when you say 1:100 is about max? their part b is "Derived from Nitric Acid, Potassium Hydroxide, Phosphoric Acid, and Magnesium Sulphate" hydro buddy tells me 'bases such as KOH cannot be used in A+B solutions'. you've said HNO3 + KOH is the same as KNO3…why would, or how can a smart company listing KOH as an ingredient?

    is it possible to calculate solution densities for use in other nutrient spreadsheets?

    best regards

  • Daniel
    September 4, 2010 @ 11:24 am

    Hello Chris,

    Thank you very much for your comment :o) Nitric acid should do the trick and all salts will remains soluble when you dissolve them in your reservoir.

    Yes, nitric acid is a liquid and usually it is available in a concentration of 30-60% so you will need to change the purity field according to the purity of the nitric acid you have. You simply need to input the purity and weight the amount of liquid you want to use.

    Regarding the 1:100 limit, it is a sound limit I established in the calculator due to the large amounts of available salts. Certainly depending on the matching of salts it is possible to make solutions with even 1:500 concentration ratios but such cases require special design. In general, to make things work for the majority of people staying at a 1:100 concentration threshold does the trick.

    The labels of companies are often very misleading since they can list any possible salt combinations to arrive to the ions they have in solution as the sources. So possibly this is just a strategy to confuse people so that reproducing their formulations becomes harder. If you don't know that you should use KNO3 instead of HNO3+KOH you would be making the solution in a much more expensive and dangerous way (since both of these substances are corrosive).

    Take into account that companies usually only list as little as they can in the most deceiving manner they can to make it hard for any possible competition. I should know, since I have formulated fertilizers for several of them through the years.

    Regarding densities, this is not possible since volumes are not additive and the increase in volume from the addition of a salt cannot be predicted accurately given the large amounts of interactions within concentrated solutions. Definitely it might be possible using a very powerful empirical model and a CAS like matlab but definitely beyond the capabilities of hydrobuddy.

    Always remember that you can add commercial fertilizers using the "Add Custom Salt" button and figure out their final ppm concentrations directly in Hydrobuddy using weights.

    I hope this answers your questions :o) Thank you very much again for your comment,

    Best Regards,


  • Daniel
    September 9, 2010 @ 4:01 am

    Hello Everyone,

    The next version of hydrobuddy – version 0.90 – has just been released. This new version includes a few small fixes to correct some errors that had been reported before plus a new feature that will make the imitation of any commercial nutrient formulation much easier. You can read more about this new feature here : http://allhydroponics.blogspot.com/2010/09/imitating-commercial-nutrients-tutorial.html. I hope you enjoy this new release :o)

    I am working on a few new features that will be implemented before v.1.0 comes out !

    Best Regards,


  • seymoor
    September 9, 2010 @ 12:26 pm

    Hello Daniel!

    Thanks for the great program, it's a very usefull!

    Here are some ideas:

    1.) w/w% or w/v%
    On the "Nutrient salts used" tab, the acid's concentrations are in w/v%, but as far as I know these are usually given in w/w%.

    So if 1ml/l 38%(w/v) HNO3 is used, it's 84.474 N, that is correct (your calc has 84,43).

    But if it's weight%, 38%(w/w) we must multiply it with it's density (in this case 1,24g/ml) so we get 104,748 N.

    2.) Adjustable error levels for macro nutrients
    It might be hard to make an algorithm like this but it would be great, it would be nice to have adjustable error levels for a few nutrients.

    So if set the error levels of P to +-5%, the program will calculate the needed salts according to this. If the goal is 100 P the recipe will have to contain between 95-105 P.
    combined error levels would be an extra, for example: 100-120N and 220-270P.

    I think, that at the moment the algorithm stops if the first element (usually N) reached the given limit, and other elements can be way off from the given limits. By allowing N a wider range of error levels, other elements could be closer to the given recipe.

    3.) Costs.
    It'd be great to have "cost" incorporited with the salts, so the cost of the recipe could be calculated on the fly.

    4.) Did you consider to make the program opensource?

    5.) An easy way to translate it would be nice to.


  • chris
    September 10, 2010 @ 5:33 pm

    Great new upgrade Daniel! Thank you!

    To clarify one point, should the solution be pH 4.0 AFTER dissolving all the potassium phosphate?

    I've gotten lots of questions of running your program on a Mac. I run it in Linux fine (except it freezes when I close it). I wonder if you can make the window maximise, so that's it's not necessary to scroll up and down (easier to read the salt list).

    it seems that when the NH4+ box is empty (no 0) I get an error " " is not a valid floating point value."

    When using nitric acid, I calculate calcium nitrate and nitric acid ppm values separately – is this right? Below 96ppm, nitric acid weight is still a negative number.

    I calculate a salt's weight with 100% purity. Say I get 72.2g. When I enter 88.5% in the purity field (nutrient salts tab), hit "calculate formula!" and the weight doesn't change. Am I doing something wrong? Do I hand calculate the 81.5g I'd need to hit my ppm? Even the 'Salts to Formulations' tab doesn't change with purity. Also, The default iron DPTA is 7%. If I have 11% Fe DPTA, would I enter 157% for purity?

    If I may ask a general question about designing fertilizer; what would you do if the guaranteed analysis didn't give any micro nutrients? Do you use a default profile? Is it connected to Phosphorus or Calcium?


  • Daniel
    September 10, 2010 @ 5:53 pm

    Hello Chris,

    Thank you for your comment :o) You should get 4.0 after dissolving the potassium phosphate. In order for the adjustment to be effective you must do it AFTER the addition if this basic salt. I would advice you to use potassium monobasic phosphate (also called potassium dihydrogen phosphate) which is already acidic. However I understand if your nutrient ratios restrict you to use potassium phosphate, in this case acidification is vital.

    Regarding running the program on a Mac the best thing would be to run a windows emulator (Sun's VirtualBox software should do the trick). This would also be the best solution to avoid problems in linux although – as you said – it works fine on wine for most uses. Regarding the maximizing I will see if I can get it done (although I cannot promise anything).

    Regarding this error with NH4+ I am not able to reproduce it. The default formulation has a 0 and gives no errors. Please post further details so that I can correct this.

    There must be an inherent problem with your formulation as the calculator should not give any negative values. You should specify the exact things you are trying to do so that I can help you debug this problem and see what is causing it.

    This problem with the purity might be a problem of the fields not being assigned correctly for some salts (when I link them sometimes I make mistakes when assigning the fields). Let me know exactly which salts show this behavior so that I can check it out and correct it. In the case of DTPA 11% you can enter 157% and the calculation should give you accurate numbers. However I will add DTPA 11% on the next release so that this can be avoided.

    If a guaranteed analysis did not include any micro-nutrients I would use a generic profile as you say, probably the micro nutrient concentrations within the default formulation loaded with the calculator would be right for almost all crops. I don't understand however what you mean regarding a link with P or Ca, the only strong link I can think about right now is perhaps between Fe and P which are antagonists (P excess inhibits Fe uptake). However let me know what you mean and I will answer your question in more depth.

    Thank you very much again for your comment :o)

    Best Regards,


  • Daniel
    September 12, 2010 @ 11:21 am

    Hello Seymoor,

    Thank you for your ideas :o) I will now comment on them :

    1) The purity is calculated as w/w percentage as all values within the "salt mass" field are input as weights. You would have to weight the nitric acid and input the purity within the purity field.

    2) This cannot be done with the current solver implementation. Implementing this would require a whole recoding of the program.

    3)Yes, this is also an idea I want to implement before v1.0 comes out.

    4)No, I like to keep the source code centralized and private.

    5)This would be nice to implement but I do not see how to do it easily.

    Thank you very much for helping me make the software better !

    Best Regards,


  • Roger
    September 17, 2010 @ 12:59 am

    Any way to increase font size in the calculator. I'm legally blind and would like to use the Nute Cal. but can't quite see it. I need about a 16 font as a minimum.

  • Daniel
    September 17, 2010 @ 12:26 pm

    Hello Roger,

    Thank you for your comment :o) Currently there is no way to do this but I will add this to the list of things to develop before v1.0 comes out. Hopefully I'll be able to make a custom field so that you can input the font. Thanks again for the comment,

    Best Regards,


  • September 23, 2010 @ 6:00 pm

    Are you kidding me? This is the best! Daniel, you’re a life saver – I was about to spend a few hours figuring out how I could use the salts I have to get what I want. You just saved me hours of head scratching.

    I cranked out my Steiner approximation in 10 minutes. The only confusion I have on it is that I didn’t select H3PO4 in the salts used, yet the formulation shows it as a component. I’m going to use H2SO4 to adjust ph. I already have bonemeal in the mix, so I’m not putting extra phosphorus.

    Once again Daniel, thanks for sharing your exceptional knowledge.

    My suggestion for your site it to put a ‘Paypal Donate’ button, so when I have some money, I can at least give you something, as can others.

    • admin
      September 23, 2010 @ 6:48 pm

      Hello Paul,

      Thank you very much for your comment :o) I am glad that the calculator is helping you get things done quickly ! Definitely the idea has always been to help people like you prepare their nutrient solutions with a reduced risk of error in a short amount of time.

      Regarding the H3PO4 you would have to be more specific about your specific problem, the calculator should not give any amount of H3PO4 if this is not selected within the list so please let me know what salts you have selected and where you are seeing H3PO4 (maybe I mislabeled something along the way).

      About the paypal donate button – great idea ! – I have just added it below the HydroBuddy link on the left sidebar in case anyone wants to contribute to this website and my efforts to develop the hydroponic calculator. Thank you very much again for your comments and interest,

      Best regards,


  • September 23, 2010 @ 7:28 pm

    Ooops, I have a problem with the calculations.

    I have K2SO4, CaNO3 (yara) and KNO3.

    When I put 170ppm N, 183ppm Ca and 320ppm K, hydrobuddy gives me 72ppm Ca (the N and K are as required). It doesn’t seem to want to use any K2SO4, even though it is selected in the salts used. Instead it uses KNO3 for nitrogen only instead of using some CaNO3 to put more calcium in, and use K2SO4 for the K.

    I hope that makes sense…..

    I can send screen shots if that would help make it clearer.

    • admin
      September 23, 2010 @ 10:12 pm

      Hello Paul,

      Thank you for your comment :o) The problem is that your salt choice is poor for the nutrient ratios you want to achieve. The calculator gives highest priority to all nutrients except Ca and S which are left as “degrees of freedom” to solve the necessary equations (since these are the nutrients plants can handle in the widest ranges). The calculator leaves potassium sulfate out mainly because it determines that it is unnecessary to use this salt (since it can fulfill its nitrogen and potassium requirements perfectly without it) if you remove the potassium nitrate you will notice that the calculator will start using it. Of course, the calculator is not perfect and it may miss some solutions, in this case you can use the “copy” option and then tweak the masses yourself within the “Salts used” tab and then get the results on the “salts to formulations” tab. In this particular case the calculator may achieve the best solution if you use Calcium sulfate instead of potassium sulfate as it will be able to have a source for the missing Ca. I hope this helps :o) Thanks again for your comment,

      Best Regards,


  • admin
    September 24, 2010 @ 3:16 am

    Hello Everyone,

    I am very glad to announce a new release of Hydrobuddy today :o) This new version of the calculator (v0.95) includes several improvements. These are the main changes :

    – Several UI changes to improve the user experience (especially on the “Salts Used” tab

    – Added a whole new implementation of costs so that you can calculate the cost of preparing a certain reservoir change. You can now specify the cost of each included or custom nutrient to calculate how much it costs you to prepare one reservoir change of a given specified volume (note that the cost of a reservoir change of the specified volume is calculated independent of the preparation type selection).

    – Added a “Download Online Database” option that allows the program to automatically retrieve an online formulation database I have created and hosted on my new website (http://scienceinhydroponics.com). Right now the database only has a few formulations but the idea is to expand this in the future to include hundreds of different choices for commercial and hobby growers.

    – Fixed a few problems dealing with certain purity fields that were not linked correctly.

    – Added Potassium Phosphate and Fe DTPA 11% as default salts

    – Added an UI improvement which allows the user to use scrollbars to move through the program’s interface if the monitor is too small to render the entire program (this allows people to use the program on netbooks :o) or screens with lower resolution).

    – Added 2 new tutorials and the field for another tutorial about the online database which will be added within the next few days.

    I hope all of you enjoy these new changes :o) As always feel free to leave a comment on my new blog (http://scienceinhydroponics.com) or any suggestions you have about new features or the improvement of current ones. Please remember that error reports are always welcome :o) Thank you very much again for all your interest and support,

    Best Regards,


  • admin
    September 25, 2010 @ 3:28 pm

    Hello Everyone,

    Today I am releasing another small update to HydroBuddy , v0.96 which contains some small fixes and additions :

    – Fixed a problem that caused people with comma as a decimal separator to be unable to save solutions without changing the values to commas. Every saving/loading procedure now uses “.” as a decimal separator, effectively eliminating this issue.

    – Fixed an error that was caused when the online database was downloaded without previously saving any formulations. The database can now be downloaded without errors even when no previous formulations have ever been loaded.

    – Added the missing link to the online database tutorial.

    – Added an “Add on top” option to the “copy commercial nutrient’s formulation” option so that now different fertilizers can be added on top of each other to determine the final ppm. This should provide a good solution for people using Linux who cannot get the “custom salt” options to work correctly. It should also help people who want to design a preparation which is a combination of several commercial fertilizers

    – Added a new “show descriptions” button which appears below the “Download Online Database” button after there is a successful download. A file detailing the description of the different available formulations is then accessible. The button reappears in the future if the “load formulations” button is pressed and a description file was downloaded in the past. This description file is also updated every time the database is re-downloaded.

    I hope you enjoy this small update :o) Thank you very much again for all your interest !

    Best Regards,


  • admin
    September 27, 2010 @ 6:57 pm

    Hello Everyone,

    A new update for HydroBuddy is out. Version 0.961 contains a small fix of a problem which made the custom salts unable to contribute to formulations. The feature now works correctly. Thank you very much again for your interest in the software :o)

    Best Regards,


  • Chris
    September 29, 2010 @ 12:37 pm

    You are really working hard! It’s much appreciated! I’ll definitely send you royalties from my (future) extensive line of massively overpriced fertilizers :o)

    hydro buddy has a 2% error when calculating weights. when you add 1L of A and 1L of B to a 100L res, you end up with 102L total volume. I get an error (related to accuracy) when I make up 1L A/B solutions. I started calculating for direct adds to a 100L res (to circumvent the error). I can input 102L, and add 10 ml/L A/B solution as normal.

    it also has a 0.5% error when copying commercial nutes. At 20 ml/usgal application rate. you end up with 3.805L total volume instead of 3.785L.

    My micronutrient profile is: Fe 10 ppm, B 4, Mn 4, Zn 3, Cu 1. They sum to 22 ppm. Say I use a 3-1-2 NPK in veg and 2-2-5 in fruiting. Each formula has different total ppm. Should micros change proportionately with each formula?

    Previously, I said I used potassium phosphate. I meant monopotassium phosphate (MKP). Generally, you use a prefix for plural atoms, and ‘mono’ is implicit. Sorry for the confusion. I had asked about certain ions blocking other ions. I was looking for an antagonist chart. A recent example is using KNO3 vs Ca(NO3)2. Obviously nitrate is nitrate…but it’s the other elements and how they interact and affect how they are absorbed by plants.

    Thank you for fixing the purity fields! I was hand calculating salt weight, and modifying the saved formula.

    In ‘copy commercial nutrient’s formula’, i’d love to see all the macros and micros in their own columns (switch Ca and S with Zn and Mn). Is there a way to switch off, or ignore micros? I have standard micro ppm, but I don’t input %w/w, so every time I hit ‘calculate formulation’ it wipes out my micro ppm. I cut and paste micro salt weights into each saved formula…but it’d be nice to do it within hydro buddy.

    What is your opinion on ‘sweetening’ agents, which just contain epsom salts? Is there a particular Mg or S ppm (or ratio) we should aim for?

    FYI, I haven’t killed anything with my DIY nutes. They look so good in fact, you’d think I knew what I was doing :o) Thanks again Daniel!

    • admin
      September 29, 2010 @ 6:23 pm

      Hi Chris,

      Thank you very much for your comment and for any contributions you make towards HydroBuddy and this website :o) As always any help to support the website and my development efforts are always welcome. I will now attempt to address the issue you point out :

      1. The addition of concentrated solutions to reservoirs is done in a 10mL per liter rate which means that the final solution level for 1L would be 1.01L. Since A and B solutions are calculated separately this leads to an error of 1.98% for each nutrient since 1L is about 0.99% of 101L. I will fix this volume addition error within the next release.

      2. This might be due to a similar problem with final volume as highlighted above. The calculator uses certain common functions so this might be the cause of the problem. I will also fix this within the next release.

      3. Generally changes in micro nutrients do not have very significant effects in plant growth after they reach the concentrations necessary for adequate growth so you will find that almost every person or commercial operation that uses different solutions for different periods merely varies N-P-K-Ca-Mg ratios and not the other nutrients. The problem is also that determining the true effect of these changes is difficult since many of the macronutrients contain some micros as impurities (which makes the control of their concentration difficult). Just work with a general micro formulation, you should have no problems.

      4. Potassium Phosphate refers to K3PO4 as you infer total substitution when no other prefixes are mentioned. In chemistry MKP is known as potassium dihydrogen phosphate which is the correct name for KH2PO4 or mono potassium phosphate. Regarding antagonism what you are looking for is probably known as Mulder’s chart, a graphic summary of nutrient interactions. You can have access to a copy here http://www.apal.com.au/site/DefaultSite/filesystem/documents/APAL%20PLANT%20NUTRIENT%20INTERACTIONS%20July%2008.pdf .

      5. You’re welcome :o) However let me know if you find any new problems with links and I’ll correct them.

      6. Well I will fix this macro-micro column issue on the next release. Also you can use the “add to current ppm values” check box in the commercial nutrient duplication window (added in v0.96) so that the values are simply added to your previous formulation without the values erasing the old ones. (it is just above the “calculate formulation” button within that window)

      7. This is quite difficult to answer and I don’t believe that the S to Mg ratio is of major importance since plants deal well with extremely varied concentrations of S ions. The ratio of S to Mg in magnesium sulfate works well and since this is one of the cheapest sources of magnesium it is the one most widely used. Certain plants however may prefer lower or higher values which you can get by using Magnesium nitrate as the nitrate source and potassium sulfate as an alternative S source. I can say that I have not read any studies on Mg to S ratios and therefore I cannot tell you what an “ideal ratio” would be. However I can say that the ratio in magnesium sulfate gives good results and that I don’t believe that variations in this ratio will bring significant improvements.

      I am glad that you have managed to prepare your own fertilizers without killing any plants :o) Definitely once you start to do it it becomes very easy and cheap. Once you get the hang of it start experimenting and sharing your formulations and fertilizers with others, certainly this is the best way to encourage people to stop buying overpriced fertilizers from this hydroponic nutrient companies. By the way if you have already saved and input many commercial nutrient formulations feel free to email them to me with some small descriptions so that I can add them to the HydroBuddy online database now downloadable through the calculator :o) Thanks again for all your interest, support and for making me make the software better !

      Best Regards,


  • admin
    September 29, 2010 @ 9:13 pm

    Hello Everyone,

    I have just released a new version of HydroBuddy (v0.97) containing some fixes and a small addition :

    – Added a label below the volume of concentrated solutions in the results tab to remind people that salts should never be dissolved over the final volume to account for volume increases created by salt additions.

    – Fixed a problem related with volume when calculating concentrated solutions in which the 10mL per L were not taken into account to address final concentrations. This eliminates a systematic error of about 2% which was present in all previous versions.

    – Fixed a similar problem with the “copy commercial fertilizer” window, now the addition volume is effectively counted as part of the final volume. This eliminates an error that could go from 0.5 to 2% depending on how large the addition is as a percentage of a liter or gallon.

    – Ordered the elements in the “copy commercial fertilizer” window so that elements are split into micro and macro nutrients between both columns

    These fixes will make the calculations more accurate :o) Thank you very much again for all your support and interest !

    Best Regards,


  • admin
    September 30, 2010 @ 10:49 am


    OK, it seems that the changes I made in version 0.97 were a bit rushed. There were actually NO errors in the calculation of any concentrated solutions but merely a problem with the way in which people were preparing their solutions. Which is WRONG. I have undone these changes in v0.971 and I have added a “how to prepare nutrient solutions” button in the Desired formulations tab so that people understand how solutions are CORRECTLY prepared. Final solution volumes should ALWAYS include nutrient addition volumes. Nutrient are ALWAYS added before a reservoir’s final volume value is reached. I am sorry for the problems introduced in the last version, version 0.971 fixes this and assumes that CORRECT preparation of solutions is always done.

    Take into account that commercial fertilizer companies calculate additions THIS way, when they say “add 20 mL per gallon of nutrient solution” they assume that the final volume WILL BE one gallon and NOT one gallon + 20 mL. Many online sources that do calcualtions in this way (several spreadsheets like PH spreadsheet do so in this way) are WRONG since they assume volume additions which should NOT be present. HydroBuddy does calculations assuming CORRECT reservoir preparations (as we chemists assume they will be done when fertilizers are designed) and therefore I can assure you that its results are accurate in this regards.

    Thank you very much again for all your interest in the calculator :o)

    Best Regards,


  • admin
    October 1, 2010 @ 3:57 pm

    Hello Everyone,

    I have been working hard on HydroBuddy and its first final release. Today I will be releasing the next version of the calculator (v0.98) which includes several improvements fixes and additions. I tested the code as thoroughly as possible and this will be a long-term release which will be replaced by the first “final release” v1.0 within the next several months. These are the fixes-additions in this version :

    – Fixed a problem with Na and Si which made the displayed final concentration of some salts erroneous (although the weights were calculated correctly)

    – Fixed a problem with H2SO4 and H3PO4 when preparing concentrated solutions (they were assigned to the wrong solution)

    – Fixed a problem with the save and load “salt list” buttons that caused the status of some salts not to be saved correctly.

    – Fixed the text displayed on text files where recipes were saved, especially when dealing with concentrated solutions

    – Added an option to prepare solutions with concentration factors different than 1:100 from now on you can use HydroBuddy to prepare more concentrated solutions (200-250) which are more in line with what commercial nutrient sellers prepare. HydroBuddy will also warn you if your concentration factor is too high.

    – The label that indicates you how many mL to add per L of final nutrient solution will update itself as concentration factors change. For example while 10mL are required for a 1:100 factor, 5mL are required for a 1:200 factor.

    – Added a feature that displays the composition as % (w/w) of the final A and B concentrated nutrient solution. This allows you to directly compare your formulation with a commercial fertilizer or with other formulations you might have created.

    After all these changes the calculator already incorporates all the things I wanted it to have before the first official final release. I will be testing the calculator within the next few months under its current implementation, correcting bugs and adding help features. Version 1.0 will probably feature an installation program, splash-screen and a lot of in-program help. Please send me any bugs or suggestions for v1.0 to dfernandezp(at)unal.edu.co. Thank you very much again for all your help and for helping me make the software better !

    Best Regards,


    • admin
      October 1, 2010 @ 10:48 pm

      The values of current (w/w%) composition in concentrated solutions is calculated by the use of some empirical assumptions since the actual weight of the final formulation cannot be known in advance due to the fact that we cannot know how much water will be needed to get to the final volume (since the volumes are not additive it is not possible to say with very large accuracy, we cannot say how much volume the salts will take up in advance). Version 1.0 will include the option to use exactly accurate (w/v)% calculations using volume and they will contain some improvements on this (w/w%) estimations. However use these percentages ONLY as estimations for comparative purposes :o) The final ppm, etc are based on final solution volume and are therefore accurate within instrumental error.

  • R R Joshi
    October 3, 2010 @ 7:02 am

    Hi Daniel
    Grretings from India ! You have made a wonderful tool. I myself had a simple excel sheet with formulas using which I have been calculating the hydroponic nutrients so far, but your program is very elaborate

    Can you include the following in your next release ( I have 0.98 version ) –

    (1) Urea – Carbonyl Diamide CO(NH2)2 to the nutrient list ? I know that it is not a direct NO3 substitute, but within 2 to 3 weeks the entire chemical converts to NO3. The ammonia starts releasing from next day of application. A research paper now asserts that it can be used in NFT Hydroponics. The reason is it is mass produced in India and is cheap !
    (2) Given the original ppms used, a curve for Conductivity Vs PPM of the solution as time passes by( assuming uniform absorption). This is because no PPM meters are available, but Conductivity meters are easily available
    Congratulations on making this tool for all hobby hydroponisists like me. I am located at Pune India !
    Thanks and with Best Regards

    • admin
      October 3, 2010 @ 10:48 am

      Hello Joshi,

      Thank you for your email :o) Sure, I will include urea within the next version of the calculator. Also you should be aware that for urea to convert into nitrate certain bacteria are needed so in many systems this might not be the case. Regarding the conductivity vs ppm curve this is a bit of a challenge since absorption depends on too many factors which I am not able to take into account. For example absorption depends on light, number of plants, ambient temperature, plant species, etc making the exercise to make such a curve probably a waste of time. Absorption is also NEVER uniforms and based on the above conditions different elements which contribute differently to the EC will be absorbed at different rates. I will not include this feature simply because it would be misleading as too many assumptions would be needed to plot this curve. Thank you very much again for your comment !
      Best Regards,


  • Chris
    October 4, 2010 @ 10:04 am

    Hi Daniel,

    I run hydro buddy in linux, no simulator. whenever i hit backspace in a field – so that there is no number – it gives me the error ” is not a valid floating point value. entering 0 in the field is fine. it’s nothing serious, i just wanted you to be able to duplicate the error.

    ‘no source of boron available’ appears twice in the warning tab.

    i’ve been playing with v0.98. i like the new features! the stock solution NPK ratios in the calculation tab doesn’t give me any nitrogen…or very little. i tried to make a 5-4-10, 1.025 g/ml, 8 ml/L, 10L stock solution 100:1.
    calcium nitrate 1924.3 g
    potassium nitrate 1296.4 g
    mono-potassium phosphate 628.4 g
    part A comes to 0-0-4.56 and part b is 0-2.87-1.51 (K and P are listed in the wrong order in the window). that comes to 0-2.87-6.07 – which is not the correct PK ratio. ‘K and P as K2L and P2O5’ is selected in the ‘copy commercial nutrient’ window, as well as the ‘change settings’ in preparation type.

    it seems to me that micros, in order of decreasing value, are Fe, B, Mn, Zn, Cu, Mo. if it makes sense to organize the fields that way, great. if not, no big deal. i think it makes sense to organize the micros in ‘copy commercial nutrient’s formulation/duplicate commercial fertilizer’s end results’ window in the same way as the ‘desired formula’ tab.


    • admin
      October 4, 2010 @ 1:23 pm

      Hi Chris,

      Thank you very much for your email :o) Yes, whenever you don’t input anything on the Edit fields the program will not understand what you are doing so it will give a floating point error. If you intend not to use any of a given element you should set it at 0.

      Sure, I will look into and correct the boron issue.

      Yes, there is a problem with nitrogen and the value doesn’t get assigned correctly for some reason. I will check this out and have it fixed for v1.0. The order is also a non-issue but I will fix it so that it displays N-P-K so that people can check the values easier. Also take note that if you want the fertilizer to have an application rate of 8mL per liter you need to make the concentration factor higher as 1:100 gives you 10mL per liter. In order to make this 8 you need to change the concentration factor to about 125. If you do this you will get much closer to the P-K ratio you want. You should also take into account that this w/w% are NOT exact as they make several assumptions regarding weights. In order to calculate this exactly you would need to experimentally determine the final weight and input it. Probably versions 1.0 will include and exact %(w/v) calculation coupled with the option to perform %(w/w) calculations if the final weights are manually input after the concentrated solutions are prepared.

      Regarding the order of the micros I guess I could change them around the program so that they always have the same order.

      Thank you very much for your suggestions and bug reports :o)

      Best Regards,


  • noha
    October 6, 2010 @ 2:17 pm

    this is a good programm and I am very glade to use it.

    • admin
      October 6, 2010 @ 6:13 pm

      Thank you very much for your comment Noha :o) I am glad you like it !

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  • Matt
    October 24, 2010 @ 3:00 am

    Works great on mac using Crossfire. Would love to see Calcium Chloride added to the list of salts. Definitely will be donating once I have some extra money to spare. Thank you so much for helping me make the leap from commercial 2-part fertilizers to custom diy.

  • Isabel
    October 30, 2010 @ 3:00 pm

    Hello Daniel: I already sent you a message but it does not appear here, so I am writing it again.
    Thank you very much for sharing your software!
    I am having some trouble using it though.
    I grow lettuces and I use a commercial formula as follows:
    Total Nitrogen (N) :8,00%
    Nitrate Nitrogen:7,50%
    Ammoniacal Nitrogen:0,50%
    Available Phosphoric Acid (P205):15,00%
    Soluble Potash (K20):36,00%
    Boron as (B) :0,20%
    Copper as (EDTA-Cu):0,02%
    Iron (Chelated) as (Fe).. :0,40%
    Total Manganese as (EDTA-Mn):0,20%
    Soluble Manganese as (Mn) :0,20%
    Molybdenum (Mo) :0,01%
    Zinc (EDTA-Zn) :0,05%
    Chlorine as (Cl), not more than:0,5% max

    For 5000 liters I use 2973 grams, 2639 grams of Calcium Nitrate (5.5 NH3 and 27.5 Ca)and 1154 grams of Magnesium Sulfate (16 % Mg).
    I am doing it as follows:
    1.- I go into the “Nutrient Salts Used” tab and select the “Add New Salt” button. A screen pops up in which I input the percentage composition values of my commercial fertilizer. I add the above percentages and save it as isabel. No problem so far.
    2.- In the “Nutrient Salts Used” tab I check the Calcium, the Magnesium and the new formula “isabel” and put the grams next to them.
    3.- then I go to the Salt to Formulation” tab and input the 5000 liters.
    The problem is that when I press the button “calculate ppm from salt weights” an error message appears: “´29,8836´is not a valid floating point value.”
    The program creates a file name “Isabel” and if I open it in the first row it appears this number 29,8836 that I do not know where it comes from.
    I do not know what I am doing wrong. Please help me.
    Thank you very much!!!

  • […] Has anyone tried The First Free Hydroponic Nutrient Calculator Program ) | Science in Hydroponics […]

  • Deepak Kukreja
    November 10, 2010 @ 6:56 pm


    One thing I want to know is that can we make changes to force the calculator to use a particular type of salt.

    For e.g

    I am trying to calculate the formula on the basis of PPM from Dr. Howard resh website for tomatomes.

    The PPM levels are given below

    N: 140 ppm
    K: 352 ppm
    Mg: 50 ppm
    P: 50 ppm
    Ca: 180 ppm
    S: 168 ppm
    Mn: 0.8 ppm
    Cu: 0.07 ppm
    Zn: 0.1 ppm
    B: 0.3 ppm
    Mo: 0.03 ppm

    But the calculator is always showing 0gm for Potassium sulphate whereas I have selected that chemical to be used.

    Also because of Potassium sulphate not being used the sulphur level is coming extremely low in the formula.

    If I remove potassium nitrate and just keep Potassium sulphate then the level of Sulphur goes very high but it then reduces the level of calcium.

    I am looking for a balance formula where I can use both Potassium nitrate and Potassium sulphate in the actual formula.

    So how can we force or define percentage of Salts should be used.. For e.g If i define potassium nitrate should not go beyond a percentage then the calculator will be forced to use potassium sulphate..

    I am not sure if this would be possible theoratically and practically also.

    Thanks & Regards,


    • admin
      November 11, 2010 @ 11:05 am

      Hi Deepak,

      Thank you for your comment :o) The problem here is that your choice of salts is poor for the concentrations you want. Try to use Calcium Sulfate in addition to Potassium nitrate and you should be able to find a very good fit. The calculator does attempt to use “mixture” of both salts but if it finds that it compromises N or K accuracy it will prefer to have accurate N and K. The calculator does its best but you should – from the start – have an adequate salt selection for the ratios you want, in this case Calcium Sulfate easily solves this problem. Of course, this makes the preparation of concentrated solutions not possible and only the “direct addition” method can be used. Also remember that you can always export the weights to the “salts used” tab and calculate the formulation for custom weights of whatever salts you want through the “salt to formulations” tab. Thanks again for your comment,

      Best Regards,


  • Jean-Luc
    November 20, 2010 @ 1:20 am

    Hi Daniel, Hi Deepak,
    I’ve composed and used Dr. Resh’s formulations. There is actually no need of a supplementary component as Calcium Sulfate. The necessary levels of K can be reached with Potassium Nitrate in combination with Potassium Sulphate and obviously the needed amount of Mono-potassium Phosphate (which is used in order to provide the needed 50 ppm of Phosphorus. There is actually no need to increase S to the required level – it’s just a result of the use of more Potassium Sulphate. to push K that high. That much S is actually not required with this formulation. The calculator is indeed a bit “overwhelmed” with this kind of formula.

    Btw: Daniel, what are your sources for the Yara Brand Calcium Nitrate you use in the salt list, is it YARALIVA CN-9 9-0-0 with 9% N and 11% Ca or YARALIVA TROPICOTE CALCIUM NITRATE 15.5-0-0 with 15.5% N and 19% Ca? Would you please check the input and specify?
    Thanks, Jean-Luc

  • […] information that may help you. First is that there is a free hydroponic nutrient calculator at: Science in Hydroponics It is written and designed by a chemist. It's a stand alone program that is continuously getting […]

  • […] permalink Thank you for your interest, I'm happy to meet some who's interested in fertilizers and nutrients. Perhaps you already knew , but a molar mass calculator can be used get the mass of an element or molecule from a formula. For example: K2O consists of two potassium(K) atom and an Oxygen(O). The weight of these atoms are different, and we want to know the mass of K, without the Oxygen. Use the K2O formula with the molar calc to get 83.01% is K 16.99% is O So to get the mass of K from K2O, multiply it with 0,8301 Sometimes MgO, or SiO, or SO3 is presented on the fertilizer's label instead of their elemental form (Mg, Si, S), this is where this calculator comes handy. Use the SO3 formula in the calc to see 40.05% of SO3 is sulfur(S), so multiply SO3 with 0.4005 to get the amount of S. You can even make a simple excel chart that will make it much more easier. This is a very good calculator which helps a lot if you mix your own fertilizers. And it's also for free: The First Free Hydroponic Nutrient Calculator Program ) | Science in Hydroponics […]

  • tester
    January 14, 2011 @ 10:12 pm

    Impressions after the first minute :
    Easier usage, it’s really improved a lot!

    But please take out those popups between the calculations cause they are killing me even after a minute.

    And a possible bug:
    Main page tab – Calculation Type –
    Click “Concentrations from Weights” then click “Input desired concentrations” and all the “Target Conc (ppm)” field became inactive, but the N-NH4

    • admin
      January 14, 2011 @ 10:51 pm

      Hello Tester,

      Thank you for your comment :o) I have fixed the bug you mentioned and uploaded an update 1.01 (both source and binary have been updated). Regarding the pop-ups, I will most likely keep them there because people tend to ignore very important errors if they do not become explicitly aware of them. On the previous versions I noticed people used calculations with instrumental errors of 100-400% without even noticing sometimes. I believe that any such errors should be reported to the user in a way in which knowledge by the user cannot be avoided (you cannot “miss” the error) as possibly very inaccurate preparations might arise from ignoring their existence. At least now people will know when problems are there and choose whether to ignore them or not :o) Thank you very much again for your comment and for pointing out this small bug ! Further comments are very welcome :o)

      Best Regards,


      PS : I will probably include an option to either enable or disable the popups when I do the next minor revision as some people might prefer not to be notified altogether :o)

  • tester
    January 14, 2011 @ 11:15 pm

    Then at least please give us the possibility to turn that off somewhere.
    I’m sure it will drive other users crazy too.
    I usually use HydroBuddy for partial calculations, not for the full recipe, so I get about 4 popups after every calculation and even after smaller “fine tunings”.

    • admin
      January 14, 2011 @ 11:32 pm

      Hello Tester,

      Thank you for your reply :o) OK, I see no reason why that couldn’t be done. I have updated HydroBuddy to v1.02 adding a check box that you can use to disable informative pop-ups (those pertaining to errors and calculation success), the check box is located near the top center of the program, above the edit box which reads “Input formulation name here”. However fatal errors – which cause the calculation to be unable to run – will still be shown. Thanks again for helping me make the software better,

      Best Regards,


  • Jean-Luc
    January 15, 2011 @ 4:23 am

    No Mac version available yet? If so where to find or click instead of “click here to dl…”? Thanks!

    • admin
      January 15, 2011 @ 12:48 pm

      Hello Jean-Luc,

      Thank you for your comment :o) Sadly I do not have a Mac or Linux machine so I cannot build the executable for any of this two operating systems. If you want you can download Lazarus (a free programming suite) for Mac and compile the source for your machine. If you do this it would also be great if you could send the compiled version for Mac to my email so that I can offer it as a download :o) Sadly since I cannot compile these executables for Mac and Linux myself you will have to wait until someone does (and emails them to me) if you do not want to build them yourself. Thanks again for your comment,

      Best Regards,


  • tester
    January 15, 2011 @ 6:55 pm

    Thank you!

    An other possible problem:
    It looks like it calculates with anhydrides.

    For example in Hydrobuddy:
    Copper Sulfate pentahydrate (CuSO4.5H2O) has
    19,841% S
    39,317% Cu

    I think this might be true for CuSO4 anhydride.

    According to this molar mass calc
    CuSO4.5H2O has:
    12.84% S
    25.45% Cu

    I also checked:

    these all have the same problem. I did not checked the other salts.

    • admin
      January 15, 2011 @ 7:13 pm

      Hello Tester,

      Thank you for your comment :o) You’re definitely right here ! I computed all those values with a website’s automatic script and it seems to have ignored all hydration levels due to the dot between the main formula and the water part. I will recompute those values within the next few minutes and upload an updated copy with the updated database within the hour. Thank you very much again for these contributions and helping me make the software better ! :o)

      Best Regards,


    • admin
      January 15, 2011 @ 7:48 pm

      Hello Tester,

      Ok, I have now uploaded v1.03 which contains an updated database with all the issues you have mentioned fixed. Please feel free to inform me about any other bugs/problems you encounter. Thanks again for helping me make HydroBuddy better !

      Best Regards,


  • tester
    January 15, 2011 @ 11:40 pm

    K2O and P2O5 are switched on the copy commercial nutes tab, so 1% K2O becomes 4364 P on the Main tab

    • admin
      January 16, 2011 @ 4:14 pm

      Hi Tester,

      Thank you for your bug report :o) The problem here is label assingment. I have fixed this problem on v1.04. Thanks again for helping me make the software better ! :o)

      Best Regards,


  • tester
    January 16, 2011 @ 1:02 am

    where does the NO3 and Cu comes from?

    • admin
      January 16, 2011 @ 4:14 pm

      Hi Tester,

      Thank you for your bug report :o) The project here is not incorrect calculation but that the label is not being updated once you change the edit field to zero. I have fixed this problem on v1.04. Thanks again for helping me make the software better ! :o)

      Best Regards,


  • Steve M
    January 16, 2011 @ 8:36 pm

    Hi Daniel,

    My first impression with the new version was “wow that’s cool”.
    I like the different “tutorial” tabs on the welcome tab. Figuring out how to save a formulation is a lot easier too.
    I found the shadow text harder to read, but I’m old :)

    I did find a bug on the Substance Selection – Add Custom box. If I make a substance and check the K and P box, then enter K2O 10 and P2O5 10 and add it to the database.
    Then select my substance and click Edit Values it shows K2O as 8.301 and P2O5 as 4.364.
    If I then do nothing except hit Update and then Edit Values again it shows K2O as 6.89 and P2O5 as 1.9.

    It seems to be doing the K -> K2O and P -> P2O5 conversion every time I edit or update the box.

    I am also seeing huge differences in the results between 0.98 and 1.04 using the same ppm settings and substances. For example I put in the following test values in both versions using 100 liters and weight in grams:
    N(NO3) 200
    P 0
    K 150
    Mg 50
    Ca 210
    S 70 and left everything else at zero.
    I used Yara Calcium Nitrate, Magnesium Sulfate, and Potassium Chloride.

    The results with 0.98 give
    MgSO4 50.71g
    KCl 28.67g
    Ca(NO3)2 yara 137.93 g

    The results with 1.04 give
    MgSO4 50.71g (same)
    KCl 150.173g (5x difference)
    Ca(NO3)2 yara 117.971 g (10g difference)

    I’m not smart enough to figure out which one is correct :) but I’m sure the plants will not like one of them.


    • admin
      January 16, 2011 @ 9:01 pm

      Hi Steve,

      Thank you for your comment and bug reports :o) I hadn’t found that bug on the P2O5 and K2O custom form and I’ll fix it promptly :o) (thank you for bringing that up),

      I am however unable to reproduce your second result. If I do the calculation for the ppm levels you mention with :

      Magnesium Sulfate (heptahydrate)
      Potassium Chloride
      Yara calcium nitrate

      For 100 L I get :


      respectively. The difference with the yara calcium nitrate might be attributed to some difference in the adjustment of salts (since the new version tries to compensate errors between Ca and N while 0.98 does not). However I am never able to reproduce your KCl 150.173g result. Please repeat this making sure you have the exact salts mentioned above and send me a pic to dfernandezp at unal.edu.co so that I can take a further look into it (if the 150g result does happen). Thank you very much again for helping me make the software better ! :o)

      Best regards,


  • admin
    January 17, 2011 @ 5:14 pm

    Hello Guys,

    I just wanted to say that v1.10, fixing all the latest bugs which have been mentioned has been released. This version also includes some important updates of the reporting part of the code as well as some small UI improvements. (salt selection list now sorts in alphabetical order automatically as well !!). Please view the changelog text file included for more details. Thanks again for helping me make the software better :o)

    Best Regards,


  • tester
    January 17, 2011 @ 6:41 pm

    substances_used.dbf is not included in ver 1.10 so it dies with an error when attempting to calculate

    • admin
      January 17, 2011 @ 7:43 pm

      Hello Tester,

      Thank you for your comment :o) Sorry, my bad ! I have just uploaded the program including the missing dbf.

      Best Regards,


  • admin
    January 17, 2011 @ 10:26 pm

    Hello Guys,

    I have just uploaded a new version of HydroBuddy (v1.11) which includes the option to perform automatic updates on startup (which includes check of version number, download of new version and unzipping of new program). This will allow you to get the latest HydroBuddy version without having to revisit the website every now and then to check on new releases. This option can also be disabled on the main tab of the program. Thanks again for all of your help in debugging the software !

    Best Regards,


  • tester
    January 17, 2011 @ 11:08 pm

    Auto update was a great idea!

    There is still some label problem with P and K

    • admin
      January 17, 2011 @ 11:26 pm

      Hello Tester,

      Thank you for your comment :o) I am glad you enjoy the auto-update feature ! I have now corrected all K2O and P2O5 issues (v1.12), everything should now be working without problems. Let me know if you find any other nasty bugs :o)

      Best Regards,


      PS : Please let me know if the Auto-Update works correctly :o)

  • feira
    January 17, 2011 @ 11:41 pm

    Hi Daniel,

    What a great software! Really appreciate your effort in developing it. I started using it from v098.
    I noticed that in the newer versions, the “concentrated type” for each substance is specified as 0, A or B (i.e, if I want to add a new substance). I tried change the “concentrated type” of each existing substances to A and target to make concentrated stock A+B solutions. The results is that all substances made stock A(in the earliest ver, the software check the compatibility and automatically assigned it to make either stock A or B. Sorry if this is not relevant, I’m a hydro noob.


    • admin
      January 18, 2011 @ 12:00 am

      Hello Feira,

      Thank you for your comment :o) I am glad you’re enjoying HydroBuddy ! On the previous version the software had the A,B,0 assignment “locked” inside the program and the user wasn’t able to change it. Now the substance edition allows you to assign this value, a characteristic which allows the user to use new substances (note that on the previous versions custom salts were NEVER used on the concentrated solution types). Whenever a substance is added you need to specify whether it can be used on A, B or 0 concentrated solutions but the program trusts this judgement and does not look any further (as the previous version did). Obviously if you change all types to A the program will simply assume that all substances go into the A solution (the same with B) and if you assign them all to 0 the program will assume that none of the substances can be used. If you do not have the necessary knowledge to change the A,B,0 components of the default database then please do NOT change them as these values have been chosen according to chemical compatibility as they were on the initial versions of HydroBuddy (you can always redownload the program to restore the previous DB makeup). I hope this answers your questions :o) Thank you very much again for your comment,

      Best Regards,


  • tester
    January 18, 2011 @ 1:09 am

    Updater dies on me:

    Win 7 64x

    • admin
      January 18, 2011 @ 1:14 am

      Hello Tester,

      Thank you for your comment :o) The updater should not be run directly from a command prompt but it should be invoked by HydroBuddy when it is started (otherwise it might not be adequately loaded). Just start HydroBuddy and the autoupdater should get executed if you don’t have the latest version installed. Note that the autoupdater may still generate an error when it tries to overwrite itself but the program should still get updated correctly. Please let me know what you get when you run the updater when starting HydroBuddy. Thanks again for helping me improve the software,

      Best Regards,


    • tester
      January 18, 2011 @ 1:15 am

      same thing happens on XP

  • tester
    January 18, 2011 @ 1:22 am

    I run the updater from CMD to see the error messages, if HydroBuddy runs it it quickly dies and I can’t see what happened because the window closes itself.
    Anyway the update does not happening.

    • charles
      January 18, 2011 @ 9:56 am

      I have the same problem.

      • admin
        January 18, 2011 @ 11:54 am

        Hello Charles,

        Please download v.1.13 which has this fixed.

        Best Regards,


  • steven
    January 18, 2011 @ 1:39 am


    kudos to your hard work and passion in hydroponics, I am fairly new to hydroponic growing but I enjoy it very much, and would like to learn as much as possible in this field….Can I ask you to write something in regards to carbohydrates/ amino acids and their effects in plants? and what is a good solution in your mind to adding carbohydrates or amino acids hydroponically in plants, specifically a replacement to products like sweet, big bud and bud candy…thank you

    I m having problems opening your latest hydrobuddy, mainly it can’t open the update.ini

    thanks again, I look forward to following your blog.

    • admin
      January 18, 2011 @ 2:15 am

      Hi Steven,

      Thank you for your comment :o) I probably don’t have the time at the moment to write articles but I will certainly keep your suggestion in mind for the future. However to give you a small preview, there are almost no scientific studies dealing with the application of carbohydrates or amino acids to soil-less crops and the few that do exist do not show any conclusive evidence regarding a positive effect of any of this two substance groups and quite on the contrary – in the case of carbohydrates – a very detrimental effect due to the increase of pathogenic micro-flora populations. To sum it up, you should know you’re spending a lot of money on an unproven concept.

      Regarding HydroBuddy, you should unzip ALL the files to the same folder. The update.ini file is included there and you should have no problem if all the files are adequately uncompressed within the same folder. Thanks again for your comment,

      Best Regards,


  • charles
    January 18, 2011 @ 2:09 am

    I have the 0.98 and downloaded the 1.2,I have extracted the files and when I try to open the hydrobuddy it will open for a second then dissapear. Looks like the same problem as others have had. I have tried opening the old version to see if it will auto update and it will not. If I try to open the new version it will only open for a split second and then dissapear. Any ideas what I am doing wrong of if somthing could be blocking it?



    • admin
      January 18, 2011 @ 3:09 am

      Hello Charles,

      Thank you for your comment :o) This update issues have now been fixed on v1.13. Please download it from the website to solve the problems. Thanks again for helping me make the software better !

      Best Regards,


  • admin
    January 18, 2011 @ 2:28 am

    Hello Guys,

    I have fixed the whole updating issue currently going on and it should now be working correctly :o) Please download v1.13 from the website, unzip all the files in one folder and run HydroBuddy. You can test the updater – only after you have run HydroBuddy for the first time – by deleting the HydroBuddy files (Except the downloaded “lastversion” file – and running the updater. It should then download the latest version and copy it to the original folder so you should see a replacement of all the files you deleted.

    On another note, within the past few days I have corrected a ton of bugs and I believe that the current implementation of HydroBuddy is now correct regarding all calculation/formulations aspects which are the ones critical for use.

    I will wait for some bug reports to gather within the next few weeks and I will issue the next update during the second week of February (probably Feb-05/06) so that I don’t have to deal with the whole updating process for very small fixes. I will also implement some features I have in mind. I hope you enjoy the current version of Hydrobuddy :o) Please leave any bug reports or issues you have here so that I can fix them all when the next version comes out :o) Thanks again for helping me make the software better !

    Best Regards,


    PS : The update is now up :o) Sorry for the small upload problems !

  • steven
    January 18, 2011 @ 5:33 am

    hey Daniel, yeah I unzip the file and everything is in the folder, but still wont open, keeps telling me unable to open the update.ini….

    thanks for the info regarding the carbohydrate/ amino acids.

    • admin
      January 18, 2011 @ 11:56 am

      Hey Steven,

      Please download v1.13 where this should be fixed. The zip file includes the update.ini file so there should be no problem if all files are unzipped to the same folder,

      Best Regards,


  • steven
    January 18, 2011 @ 6:57 pm

    v1.13 downloaded… same issue. working on v.1.03 for the time being…

    • tester
      January 18, 2011 @ 7:57 pm

      it’s working for me.
      The uploader is ok too, it downloads the zip file. I’m curious if it will work or not when it really needs to update.

  • Wapang
    January 19, 2011 @ 3:44 am

    Hi Daniel
    Your Hydrobuddy is boon to many of us here. You have done a terrific job. Thanks a million and keep up the good work

  • tester
    January 26, 2011 @ 5:22 pm

    The names of added custom substances are not shown on the “Detailed element contributons list” tab.

    • admin
      January 27, 2011 @ 7:10 pm

      Hello Tester,

      Thank you for your comment :o) All custom decompositions are accurately shown within the ‘Detailed element contribution list’. If the custom substance you have intended to use is NOT shown it means that it is NOT contributing in anyway (not used within the final solution). Please check the list of calculated weights to see if this substance shows. If it doesn’t show there then everything is OK (substance does not contribute) if it does show then please send me an email to dfernandezp at unal.edu.co with a screenshot of the problem and the elemental makeup of the custom addition. Thanks again for helping me make the software better !

      Best Regards,


  • tester
    January 29, 2011 @ 5:28 pm

    Sorry the problem was on my end, I did not filled in the formula for the substance, and that would have been shown on the detailed element contribution list.

  • January 31, 2011 @ 7:26 am

    Hi Daniel,
    Love the program, however i have some issues, after entering element salts i use saving them in the DB. after a update check ~gone~ back to default. noticed the formulations also ~gone~
    am i doing something wrong?.
    wish list is the option to include a element in the formulation that it has to use, then calculate using that element and the rest in the list. this would be great as i have to make allowance in the base formulation to do this at the moment. maybe a tic box? or a % to use.
    many thanks for all your hard work.

    • admin
      January 31, 2011 @ 3:51 pm

      Hi Joe,

      Thank you for your comment :o) Formulation and substance databases are currently being overwritten by the current update package but when the next version of HydroBuddy is released they will be adequately preserved and merely updated using any new additions obtained from the update source. Once a new version comes out the automatic update procedure will NOT overwrite your databases as merely update instructions will be included within the updating package.

      I do not understand very well your “wish list” item. What do you mean by “include an element in the formulation that it has to use” ? Currently HydroBuddy searches for the best mathematical solution to a given problem and therefore it doesn’t seem to make a lot of sense to “force” the program to use a certain amount of any element as any solution obtained in this way will be different from the optimal one. Certainly you might want to explain this a little bit better as I may have misunderstood your explanation :o)

      Thanks again for your comment and you’re welcome for the hard work,

      Best Regards,


  • steven
    January 31, 2011 @ 6:56 pm

    I’m xp and windows 7 running on parallels app for the mac, both is giving me the same problem with problem opening the update.ini file…..
    i uncompressed everything when i download it in one folder and still the same issue, I would really like to use your app but can’t seem to open it, cause i would like to replicate advanced nutrients big bud since i bought all the salts and all.. thanks


    • admin
      January 31, 2011 @ 8:47 pm

      Hello Steven,

      Thank you for your comment :o) The windows binaries are meant to be used on a NATIVE windows desktop. Bear in mind that I do not have a Mac or parallels so I cannot provide support for this type of crossover software. If you would like to use the program on a Mac then the best thing should be to compile binaries for your operating system using Lazarus’ Mac version. I would love to help you do this but since I do not have access to a Mac I simply cannot get this done. If you want to use the program’s current binary then please do so on a windows native computer. Thanks again for your comment,

      Best Regards,


  • January 31, 2011 @ 9:12 pm

    Wishlist explained.
    some elements i use Organic bases. these have lots of different elements some in small amounts other larger. at the moment i subtract the ppm from the base formulation. then use the mineral salt to top up to the formulation. when i include the organic bases in the substance selection it finds the easiest way. (makes sense) missing out some of the organic chelate elements. i would like to force the program to use minimum of X amount of these and formulate around them.
    many thanks,

    • admin
      January 31, 2011 @ 9:36 pm

      Hello Joe,

      Thank you for your comment :o) I still do not understand what you mean, what do you mean by “subtract the ppm from the base formulation” ? What do you mean by “organic bases” ? Please send me an email to dfernandezp at unal.edu.co with detailed screenshots showing the composition of the salts you’re using and other screenshots explaining in detail what you want to do. I will be happy to implement the feature you want once you explain it to me in a way in which I can understand it. Thanks again for your comment,

      Best Regards,


  • tester
    February 1, 2011 @ 12:31 pm

    I’d also find it useful to have the possibility to force the program to use the given substances, even if there are better ways to reach the closest nutrient content.
    For example when I have a custom fertilizer (substance) that also contains triacontanol, and I want to use that in a mix, but Hydrobuddy would not want to use it because it thinks it’s better to supply the whole K with KNO3.

    An even better solution would be to have spinbuttons by the elements, and even by the gross errors for different elements. (see the attached pic here http://img638.imageshack.us/img638/2043/programmanager20110201.png )
    By adjusting the gross error for an element, we could force Hydrobuddy to find an other solution thats let’s say fits for P, and not N.

    For example 100N, 50P is the goal but the closest match Hydrobuddy could find is 100N, 75P, by adjusting the gross error it could find an other match that fits or closer to P instead of N, like 80N, 50P.

    • admin
      February 1, 2011 @ 4:59 pm

      Hello Tester,

      Thank you for your comment :o) I have just finished implementing a feature which enables users to input fixed additions of certain substances which the program will use as constraints for the development of formulations (therefore allowing you to use substances which the program would have decided not to use otherwise). However the spinbutton feature will NOT be implemented since the program does not “solve for an element” but simply finds the best mathematical solution to the problem. The code simply does not allow me to tell the program to find a worse solution, the errors and values obtained are OUTPUTS and cannot be used as INPUTS for the calculation. Hydrobuddy’s solution is the best mathematical compromise between all values it does NOT solve for any particular element and therefore changing from the best solution to one that favors a specific element is not possible. However I have implemented another small feature which allows you to change the element used as “degree of freedom”, something which may allow you to obtain solutions that favor different elements (depending on your substance inputs). The newly implemented features will be released with the next version during next week. Thanks again for your comment,

      Best Regards,


  • crystallattice
    February 3, 2011 @ 7:25 am

    Hi Daniel,

    I’m having problems running your program. I keep getting a “List index(0) out of bounds” and a option to cancel/quit and an option to continue and risk data loss. Either way I can’t get it to run. I’ve tried it on both XP SP2 and on Vista Home with no luck. Please advise if I need to install some runtime.


    • admin
      February 3, 2011 @ 11:37 am

      Hello CristalLattice,

      Thank you for your comment :o) There are NO runtimes needed. Please make sure you’re running the program on NATIVE windows machines (virtual machines are NOT supported) and that ALL FILES are placed within the same folder. Please email me a screenshot of the error to dfernandezp at unal.edu.co along with a description of when it happens. Thanks again for helping me make the software better,

      Best Regards,


  • crystallattice
    February 3, 2011 @ 7:05 pm

    Hi Daniel,

    I’m sitting here at home, busy on the net, and thought I’ll give your prog another try and bang! it works! The solution or problem is the firewall at work and the fact that I’m not always connected to the net at home. It seems like your auto update routine is causing an error if it can’t get through to the net.

    Fix that and I’ll be able to play with your neat prog at work. I need to as it looks like I’ll need a few hours to learn how to use all the advanced stuff.

    Keep up the good work and thanks for making it free!


  • crystallattice
    February 4, 2011 @ 7:48 am

    Hi again Daniel,

    Quick fix: Open Update.ini and change to “update = 0” now it works!


    • admin
      February 4, 2011 @ 10:52 pm

      Hi CrystalLattice,

      Thank you for your reply :o) The problem should now be solved on the newest version – v1.20 – which checks for connectivity before attempting to run the updating process without the need to disable automatic updating. Thanks you for helping me make the software better,

      Best Regards,


  • admin
    February 4, 2011 @ 9:20 pm

    Hello Everyone,

    Thank you for all your help and feature suggestions :o) I have finished all the implementations/fixes/additions I had in mind and have just released v1.20. The next release (v1.30) will be out in one month. Here is a copy of the changelog :

    v.1.20 – Major release

    – Fixed an error with the updating of the formulation combobox on startup

    – Added check for update.ini on startup to prevent errors on some virtual machines

    – Added new updating functionality which updates databases without overwritting user-additions

    – Added many formulations from various online sources

    – Implemented some reliability checks on the preparation of concentrated solutions so that users do not prepare solutions with obvious chemical incompatibilities

    – Redid several aspects of the calculation procedure to allow the setting of “fixed minimal quantities” of any one of the used salts. By selecting a given weight within the substance selection screen the program will use a certain minimum weight as a constraint.

    – Made the degree of freedom used in calculations a selectable variable (users can now select different elements as degrees of freedom if the default does not give adequate results)

    – Added a “small window mode” so that users on netbooks can use the program

    – Made all windows fixed size in order to avoid problems/crashes related with the auto resize lazarus implementation

    – Added a lot of nice UI icons to make the program nicer :o)

    – Added ping check in order to avoid trying to update when there is no internet connection

    – Several small bug fixes… :o)

    To those of you who are using the auto-update mechanism please let me know if all software/database updating is done correctly in an automatic fashion (was done correctly on my tests). Also those of you who were having trouble with the update.ini not being found should no longer have this problem on virtual machines (the program should run). Please post any bugs, suggestions or feature requests for the next version :o)

    Best Regards,


  • Doug
    February 5, 2011 @ 9:53 am

    In your database, for the Yarra Calcium Nitrate, you list NO3- as 15.5% and NH4+ as 1.1%. However, on my bag of YarraLiva CALCINIT, it lists the total N as 15.5% made up of 1.1% NH4+ and 14.4% NO3-. I am not sure if this is an error in your database or if we have a different product?

    Also, I was surprised to see that your Borax contained Fe. Again, is this an error in your database, or is it something that actually exists in Borax?

    • admin
      February 5, 2011 @ 11:37 am

      Hello Doug,

      Thank you for your comment and for noticing these bugs :o) These two errors will be corrected on the next release,

      Best Regards,


  • Steve M
    February 5, 2011 @ 11:04 pm

    Hi Daniel,

    Love the new GUI icons and the Reset Weight button. They look very nice.

    The auto-update downloaded the zip file and opened a command prompt window which just sat there for a while. But when the command prompt closed and I clicked on HydroBuddy icon again it still said I had to update. It looked like some of the files were updated since the date changed on them. I did have a zip file in the directory. I manually ran the hydrobuddy_updater.exe and then it worked. Is that how you’re supposed to do it?

    Looking thru all the formulations I noticed you have the formula author/source as part of the formula name. Maybe on a future update you could split that in the database and have fields for formula name, source, and notes. The notes could tell you things like “For tomatoes grown in Perilite using drip irrigation in Florida greenhouses”.

    I noticed you now sort the formulation names in the list which is a nice feature.

    I haven’t tried the “use this minimum amount of substance” feature but it sounds interesting. Another thing I wish for is a “maximum ppm”. Mainly for Cl since I try to keep Cl levels under 75ppm in my formulas. Na might be another one to limit.

    I eagerly wait to see the cool stuff you put in the next version!


  • Ian
    February 8, 2011 @ 12:05 am

    Hey Daniel

    You have a great program here. I do have a question about liquid products that are given as grams in the tank breakdowns. For example Nitric and Phosphoric acid are obviously liquid products but the recipe is given in grams. How can I work this out to get the correct L or fl oz number? I think for it to work in your program you need a weight/gallon in the substance composition section. Am I just missing something here?

    Thanks for your help


    • admin
      February 8, 2011 @ 2:51 am

      Hey Ian,

      Thank you for your comment :o) Please remember that you can also weight liquids (simply tare a cup and add the liquid) !

      Best Regards,


  • Michael
    February 9, 2011 @ 9:42 am

    fantastic calculator! small problem in database. zinc sulphate dihydrate values calculated are anhydrous values.

    • admin
      February 9, 2011 @ 12:10 pm

      Hello Michael,

      Thank you for your comment :o) I am glad you like the software ! I have taken note and will correct this within the next update,


  • Michael
    February 9, 2011 @ 10:04 am

    sorry one more small error. copper nitrate hexahydrate has a value of 7 for Fe in the database.

    would also love to know more about how the EC predicted values are calculated.

    • admin
      February 9, 2011 @ 12:11 pm

      Hello Michael,

      Thank you for your comment :o) I have taken note of this error as well. Regarding the EC values, they are calculated using a semi-empiric approach based on some simple mathematical manipulation of limiting molar conductivities. You can checkout the code to find out exactly how this is done. Thanks again for your comment,

      Best Regards,


  • acidblue
    February 10, 2011 @ 3:16 am

    I got this to run in Ubuntu 10.04 under wine.
    In case anybody cares
    So far it works fine.

  • tester
    February 12, 2011 @ 1:18 pm

    I had a chance to look into an other fertilizer calculator, Nutron 2000+ that goes for 105$.

    All I can say is that Hydrobuddy is WAY BETTER than the Nutron software.

    • admin
      February 13, 2011 @ 11:11 pm

      Hello Tester,

      Thank you very much for your comment :o) It is definitely great to see that HydroBuddy is much better than commercial calculators ! However if you see any features on commercial software currently missing on HydroBuddy please let me know so that I can add them to future versions. Thank you very much again for your support :o)

      Best Regards,


  • tester
    February 14, 2011 @ 12:38 pm

    Well it’d be great to have units like mmol/l, meq/l, mol/l.
    Adding acids (liquids) by volume instead of their weight would be useful too, I have the density tables if you are interested.

    At the water page, a conversion between GH, total alkalinity etc would be useful too.

    • admin
      February 14, 2011 @ 9:25 pm

      Hello Tester,

      Thank you for your comment :o) After a lot of work I have implemented your first suggestion, so the next release will have the ability to do all calculations in either mmol/L, ppm, meq/L or mol/L. Regarding the acids, I am a little bit reluctant to do this since it would require the addition of at least two additional fields to the database (a density field and another field to know whether something is a liquid or not) so I would need to develop a whole database field updating solution which I don’t have yet. However if I have the time I might be able to get this done :o). Regarding the water page, it has the same field problem regarding the water quality database but again, if I have the time I’ll get it done :o). Feel free to leave any additional suggestions you may have ! Thanks again for helping me make the software better,

      Best Regards,


  • tester
    February 15, 2011 @ 12:10 am

    wow that was fast, thank you!

    • admin
      February 15, 2011 @ 10:04 pm

      Hello Tester,

      Thank you for your reply :o) Well luckily I had a quite a bit of time during the past few days and I was able to code all the features you requested. The next version will allow you to get results for liquids in mL and to select the density and state (liquid/solid) of any additions or current elements within the DB. The update will also keep your database records intact so you will not lose any of the information you have gathered. There is also now a section dedicated to pH/GH/KH within the water quality section. Please let me know about any other features you might consider useful :o)

      Best Regards,


  • Cue Bossa
    February 17, 2011 @ 2:45 am

    Thanks for the software Daniel! Excellent work!! Quick question, I am adding a custom substance, L-Arginine, a common amino acid and am unsure of whether to list it as a nitrate or?? Also curious as to how the cost and purity tabs play into the formulation. Thanks for all your hard work.

    • admin
      February 17, 2011 @ 10:43 am

      Hello Cue,

      Thank you for your comment :o) Nitrogen from amino acids is neither N as nitrate nor N as ammonium although it would be better approximated as the second rather than the first. The cost value doesn’t have any effect on overall calculations but it is merely a feature to help you know the total cost per preparation. Simply input your cost per kg and the program will print the cost for the substance for each preparation under the last column of the results tab (the cost column). Purity does affect calculations directly, the more impure a substance is the more has to be added to reach a certain threshold requirement. Please read this article so that you understand what purity is : http://scienceinhydroponics.com/2010/09/understanding-reagent-purity-and-its-importance-in-hydroponics.html. Thanks again for your comment,

      Best Regards,


  • Cue Bossa
    February 21, 2011 @ 8:01 pm

    Daniel, I am getting the following message when carrying out calculations “Gross errors on Fe are too high, probably an adequate solution was NOT found.” Not sure of what the issue is.

    • admin
      February 21, 2011 @ 8:44 pm

      Hello Cue,

      Thank you for your comment :o) This means that the error on Fe is way too high, something which means that an adequate solution was probably not found by the software. This happens whenever you use too many substances or your substances are a very inadequate match for the formulation you want (remember that not all salt choices can generate all formulations due to the fact that achievable proportions are fixed within your salt choice). If you want you can post a comment with your salt selection and formulation or send me an email to dfernandezp at unal.edu.co so that I can help you further debug the problem. Thanks again for your comment :o)

      Best Regards,


  • admin
    March 4, 2011 @ 1:04 pm

    Hello Everyone,

    The latest update for HydroBuddy (v1.30) has just been released. Here is a copy of the changelog :

    v.1.30 – Major release

    – Changed the UI to use the GTK 2 tool kit for better compatibility with Mac and Linux machines when compiling native binaries
    – Changed results from listboxes to string grids which offer much clearer output
    – Added nutrient ratio analysis button to results tab. Custom nutrient ratios can also be calculated besides the defaults. This is very useful for nutrient solution evaluation.
    – Fixed several errors dealing with Fe on some metal salts
    – Fixed zinc monohydrate compositions values
    – Added concentration units selection. Calculations can now be done in mM, mN, M and ppm
    – Instant conversion between different concentration units is implemented
    – Added liquid/density options in the substance edition screen so that calculated liquids can be displayed as mL instead of grams or ounces.
    – Fixed a few bugs dealing with the data log tab regarding the default database selection, analysis button, etc.
    – Added new update functionality which allows new database fields to be added to existing databases
    – Added new pH/KH/GH fields to water quality analysis. Although these values are not yet used by the program they can be saved and converted between drops/ppm. Future versions will use this values to warn users about potential problems.
    – Added many more UI icons to make the program look better :o)
    – Several additional bug fixes and small feature additions :o)

    With the next update I intend to include Mac and Linux binaries (this was the main reason for changing to the GTK toolkit on this version). Feel free to leave any bug reports, feature requests or suggestions,

    Best Regards,


  • tester
    March 4, 2011 @ 3:39 pm

    “The program can’t start because libgdk-win32-2.0-0.dll is missing from
    your computer. Try reinstalling the program to fix this problem.”

    Fresh install (not update)

    • admin
      March 4, 2011 @ 4:41 pm

      Hello Tester,

      Thank you for your comment :o) As Ruben said on his comment you need to install the GTK+ Runtime Environment (http://sourceforge.net/projects/gtk-win/) . I hope this helps :o)

      Best Regards,


  • Ruben
    March 4, 2011 @ 4:24 pm

    its necesary install GTK+ for Windows Runtime Environment (http://sourceforge.net/projects/gtk-win/) now… my program run ;)

  • Steve M
    March 5, 2011 @ 12:30 am

    The new version looks nice. I like the grid display on the results tab. That is a lot easier to line up substances with their amounts.

    One issue I’m seeing is if a substance isn’t used it gives the “not used” pop up but then gives an error box saying “” is an invalid float. Press OK to ignore and risk data corruption. Press Cancel to kill the program.

    Pressing OK doesn’t appear to hurt anything and you do get values on the results tab. But it makes me wonder if I’m silently corrupting the databases…

    I also noticed the cost information for the substances was over written with the default 100 instead of migrating any user supplied values.

    I found all the “database updated” pop-ups really annoying after the 10th one :)

    • admin
      March 5, 2011 @ 12:23 pm

      Hello Steve,

      Thank you very much for your comment :o) I am glad you like the new version ! I am currently working on the Linux/Mac binaries and within a month I will be releasing a version for each one of the different operating systems. Thanks to GTK+ this is now possible. Regarding the errors, I will look into the “not used” pop up error you mention and see if I can reproduce it, probably the error is related to some of the StringGrid changes I carried out. However rest assured you’re not corrupting the database. I will also correct the cost overwritting issue. About the popus, this update had a LOT of popus because the liquid/density variables were added to ALL substances, I will however add a checklist to disabled them. Thank you very much again for helping me make the software better :o) Any feature requests are welcome !

      Best Regards,


  • Jean-Luc
    March 6, 2011 @ 6:55 am

    Hi Daniel,
    If compiling the/a Mac (OSX) version, please consider that it should at least be OSX 10.4.X (Tiger) downwards compatible. Many (especially old school) folks do not have necessarily upgraded to Leopard or Snow Leopard (perhaps Lion) yet. Should/could be for UB though.


    • admin
      March 7, 2011 @ 2:28 am

      Hi Jean-Luc,

      Thank you for your comment :o) The latest version of HydroBuddy (v1.31) now has MacOS-X binaries for download. You can use this binary to run Hydrobuddy natively on your Mac. This version was compiled on Leopard but it should be compatible with previous versions of MacOS-X.

      Best Regards,


  • Jean-Luc
    March 6, 2011 @ 7:09 am

    Btw: just tried to launch v. 1.30 with Crossover (8.0) on my iMac and it obviously doesn’t launch anymore. Probably because (at least with this version of Crossover) it doesn’t have anything like GTK+ Runtime Environment installed, nor can it be upgraded to have it running – I suppose. Upgrades and new features (that come with GTK+ Runtime) are certainly nice, – but if I can’t run the soft anymore with Crossover, I (an probably a few others) am/are simply not able to use it any longer until there is a Mac version available. :-(

  • admin
    March 7, 2011 @ 2:26 am

    Hello Guys,

    I have just updated HydroBuddy to v1.31 (A long term release). Here is a copy of the changelog :

    This release is the culmination of a lot of effort :o) From this release binaries for Mac and Linux will be available for download as well as binaries for Windows. The program is now installed using a Full fledged installer that makes installing easier on all the different platforms :o)

    – Fixed updating of user defined costs when updating to a new version (costs are no longer overwritten)
    – Fixed issue dealing with exception when a salt was not used
    – Changed “degree of freedom” selection to drop down combo box (makes more sense)
    – Fixed other small bugs

    As you can see the program has faced a major step forward with the release of the first version with binaries for several different platforms :o) Please let me know about any bugs/problems/suggestions so that I can take them into account for the release of the next version in May. Thanks again for all your help and support :o)

    Best Regards,


  • Jean-Luc
    March 7, 2011 @ 8:08 am

    Hi again Daniel,
    Unfortunately the OSX version doesn’t download as an installer. When clicking “GET H.B. for Mac OS X” using Safari, a text file opens in a new browser window. Only if clicking the Button while holding cltr, the file can be downloaded when choosing “download file as” from the pop up menu. Although Firefox downloads the file directly, the installer is corrupted and does not show up with the proper icon (and without the .app extension) and will thus not install on a double-click nor with other options. I even tried to add the .app extension after dl. Please compress the installer on the OS X machine in either .sit, sitx or even .zip format BEFORE uploading to the server or before copying it to any Windows machine. Otherwise the installer will obviously get corrupted in the process. It’s a classic problem with uncompressed UNIX executable files and it can (only) be solved as described. Thanks!


    • admin
      March 7, 2011 @ 11:53 am

      Hi Jean-Luc,

      Thank you for your comment :o) The installer WORKS CORRECTLY. The problem is that it is NOT a regular app installer and you CANNOT open it by double clicking. In order to open the installer please execute it FROM A TERMINAL using the “./” command. Simply go to the directory where the installer is within a terminal and execute the command ./HydroBuddy-1.31-MacOS-X-Install. Again, this file CANNOT be opened by double-clicking you need to execute it from a terminal. I have confirmed on a few Macs that it works this way. Thanks again for your comments,

      Best Regards,


      • admin
        March 7, 2011 @ 1:08 pm

        Hello Jean-Luc,

        I have created a proper .app file which you can launch directly by double clicking. Just download the zip file and you should be able to execute the installer right away. Please bear in mind that shortcut creation and end-of-install execution is not working yet on Macs and Linux so you’ll need to browse to your install folder to execute HydroBuddy. I hope this is much easier now :o)

        Best Regards,


  • Jean-Luc
    March 9, 2011 @ 1:59 am

    Thanks for the effort Daniel – but as much as I would give good news, the”proper” OS X.app does not launch any installer on my machine (with Tiger?) – no way. And usually I have NO trouble ever with installers, unless they say they say that the version is incompatible with my system. Btw: don’t even bother with things like shortcut creation for Mac users, as it works differently on MAC OS X anyway. Some installers may ask if you would like to have an alias of the app in the Dock (sort of a shortcut), but installing to the application directory/folder and an user defined installation directory option is truly all that is needed. Any app can be easily dragged and dropped afterwards to “the dock” manually in a second.

    And again, as for the previous way to install via the terminal (unix shell): I am not picky and Mac user since over 20 years. But that was kind of a tall order for any average Mac user. It’s like you would ask to use the MS-DOS command prompt window, to launch the windows installer LOL. With the terminal open, although the command line was correct and I managed to type it in – I got a permission denied message, when trying to run the installer – obviously as I was logged in as an user, not as a admin or superuser ;-)

    • admin
      March 9, 2011 @ 2:20 am

      Hello Jean-Luc,

      Thank you for your comment :o) As I tell you I have tested the installer on Leopard (10.63) and it worked correctly, the installer is however like a “regular app” not a proper Mac dmg installer since I didn’t use Apple coding tools to build this (but Lazarus and install jammer). It may be possible for this installer to be incompatible with previous MacOS-X versions but sadly I lack any Tiger Mac in which I can run tests, etc. Therefore it is hard for me to provide support for older versions. In any case the installer should be executable through the command prompt as I described before. You should not be logged in as admin or superuser to run the installer but you might need to give it running permissions (chmod +x InstallerFileName). I hope this helps :o)

      Best Regards,


      PS: If you keep having trouble with this installer send me an email and I’ll email you a standalone copy of the hydrobuddy.app file so that you can run the program without having to launch the installer :o)

  • Mick
    March 9, 2011 @ 10:05 am

    Hi Daniel I am using Mac OS X Snow Leopard 10.6.6 and I had no trouble at all installing HydroBuddy 1.31, works just fine and Thank you very much. The only thing I have noticed in the Substance Selection is the EDTA Chelated Mn, Cu, and Zn are no longer on the list.

    cheers Mick.

    • admin
      March 9, 2011 @ 2:54 pm

      Hi Mick,

      Thank you for your post :o) I am very glad to see the program is working for Mac OS users ! Regarding the substances, I will add them within the next version of the program (I will also publish a procedure on how to update databases on Mac/Linux while preserving any changes you may have made). Thanks again for helping me make the program better,

      Best regards,


  • David
    March 10, 2011 @ 8:13 pm


    Love your product! I’ve tried the windows and linux versions and they work perfectly!

    My question is, how do I add trace element mixes as an custom substance? I am trying to add Jack’s Professional MOST Mix of Soluble Traces or Peters Professional STEM soluble trace element mix.

    For example, Jack’s Professional MOST Mix of Soluble Traces is listed as
    Sulfur 13.00%
    Magnesium 0.40%
    Boron 1.35%
    Copper 2.30%
    Iron 7.50%
    Manganese 8.00%
    Molybdenum 0.04%
    Zinc 4.50%

    I am just trying to make sure that I don’t give too many micro-nutrients.

    • admin
      March 10, 2011 @ 8:48 pm

      Hello David,

      Thank you for your email :o) I am very glad you like and enjoy HydroBuddy! Regarding your question, simply go to the substance selection screen and click the “Add Custom” button. After you do this you’ll be able to enter the composition percentages within each element’s box. Input any name on the “Name” field and input a short indicative within the formula field (something like JackMST, it doesn’t matter since this value is just used as a reference), leave purity at 100% (since you’re giving an input based on analysis of the whole substance) and add the new substance to the “used substance” list by selecting it and pressing the “Add” button. After this you’ll be able to use it in calculations either to know how much to add for a given formulation or to know the resulting ppm by setting a weight using the “set weight” button (after setting the calculation to “Concentrations from Weights”). I hope this helps you with HydroBuddy :o) Thanks again for using my software !

      Best Regards,


      • David
        March 10, 2011 @ 9:20 pm

        Thanks for the reply. The only problem is it keeps giving me a high Cu. Is 2.1 ppm of Cu too high?

        My book Soil Fertility and Fertilizers (2005 7th Edition) say that normal Cu concentrations in plant tissues range from 5 to 20 ppm, however soil concentrations average around 9ppm.

        TOMATO PLANT CULTURE: IN THE FIELD, GREENHOUSE, AND HOME GARDEN says that Cu concentrations greater than 0.1 mg/L (ppm) can cause toxicity.

        Does that mean having 2.1ppm in my solution is too low or too high?

        • admin
          March 10, 2011 @ 9:34 pm

          Hi David,

          Thank you for your reply :o) In hydroponics 2.1 ppm of copper is WAY to high. You would need to have only 0.01-0.05 or up to 0.1-0.2 at MOST. It is probable that your fertilizer is not geared for hydroponics but for soil use and for this reason copper might be higher (foliar fertilizers are usually very high in copper to aid in fungal disease prevention for example). This fertilizer might NOT be appropriate for hydroponic use if it has such a high Cu concentration. Thank you very much again for your comments :o)

          Best Regards,


  • praveen
    March 11, 2011 @ 7:15 am

    Hi Daniel,
    How much should i dilute the Nutrient solutions when the outside temp is high and the humidity is high. What is the relation between temperature and the concentraion of the nutrient solution. Will the nutrient soultion composition or concentration change with changing temperature for vegetables.In my area the temperature is always between 23C – 36C with high humidity. Please advice the best option to grow vegetables.

    • admin
      March 11, 2011 @ 6:22 pm

      Hi Praveen,

      Thank you for your comment :o) However I do not provide custom consultant services outside of support for HydroBuddy. There are many forums within the web where you can find people who will be more than willing to answer your questions. Please limit future comments on this post to matters dealing with HydroBuddy,

      Best regards,


  • Alsagaff
    March 11, 2011 @ 6:12 pm

    Hi Daniel,
    Firstly i must thank you for the software, as it has tremendously help me understanding and creating the nutrient i required. But, with the new Hydrobuddy v1.31 for Window, the following message appear ” The procedure entry point deflateSetHeader could not be located in the dynamic link library zlib1.dll” and the program could not activate.Same thing happen i download on other computer. I sincerely appreciate if you help to resolve this problems.
    Once again Thank you.
    Best Regards

    • admin
      March 11, 2011 @ 6:20 pm

      Hi Alsagaff,

      Thank you for your comment :o) I am unable to reproduce your problem on Windows 7. Please specify the version of windows you’re using. Try the following steps to see if the problem gets fixed :

      * execute HydroBuddy as Administrator
      * Install GTK manually from gtk.org

      If these suggestions do not fix the problem please post your version of Windows. Also please ensure you’re installing HydroBuddy using the latest installer. Thank you very much again for your comment,

      Best Regards,


  • Alsagaff
    March 11, 2011 @ 9:13 pm

    Hi Daniel,
    Thank you for your feedback. I will try base on your suggestion and shall get back to you soon.
    FYI, both of the computers running on Window XP Home edition.

    Best Regards

  • Cue Bossa
    March 11, 2011 @ 10:03 pm


    Awesome to see a release for OSX! However, I am having difficulties adding custom substances. I get an error message looking for a .dbf when I want to save a custom compounds info. Thanks again Daniel!

    • admin
      March 12, 2011 @ 12:49 pm

      Hello Cue,

      Thank you for your comment :o) I am unable to reproduce the problem (On Snow Leopard 10.63). Please post the exact error you are getting. Thanks again for reporting the problem,

      Best Regards,


  • tester
    March 17, 2011 @ 2:28 pm

    Perhaps solubilities could be also incorporated.

    • admin
      March 17, 2011 @ 4:17 pm

      Hello tester,

      Thank you for your comment :o) I haven’t included solubilities because they change dramatically (even by 100x) depending on ionic concentrations, common ion effects, pH and ionic activity coefficients, therefore it would be dangerous to include any solubilities since they could lead to wrong preparations because of wrong assumptions. The above mentioned effects cannot be easily predicted so I would not dare include any sort of solubility based criteria. Thanks again for your comment :o)

      Best Regards,


  • Cue Bossa
    March 18, 2011 @ 6:12 pm


    I am having issues saving custom substance edits and formulations to DB in OSX. I’m just wondering if you have had any issues with this. Thanks in advance.

    • admin
      March 18, 2011 @ 6:23 pm

      Hi Cue,

      Thank you for your comment :o) As I said before I am unable to reproduce this problem please post the EXACT error you’re getting so that I can debug the issue. Thanks again for helping me make the software better :o)

      Best Regards,


  • Cue Bossa
    March 18, 2011 @ 6:43 pm

    I opened HydroBuddy this morning to find all substance edits erased as well as the formulations I added to DB. Upon adding and editing them all back in over the last hour I was able to close the program and reopen the program with all the information being retained. Not sure…… is the OSX version auto-updated? thanks again

    • admin
      March 18, 2011 @ 7:23 pm

      Hello Cue,

      Thank you for your comment :o) The OsX version does NOT carry out any updates (updating sections are not even included within the code). Most probably there was some sort of permission issue which caused the databases to be rewritten the first time you modified them. Let me know if the problem happens again,

      Best Regards,


  • Kirk
    March 19, 2011 @ 6:05 pm

    We are running on Windows 6 64-bit and seem to be getting a file corruption error.
    The error appears on substances_used.dbf.

    • admin
      March 21, 2011 @ 9:52 pm

      Hi Kirk,

      Thank you for your comment :o) Please make sure the dbf file is located within your installation directory or try running HydroBuddy as admin. If the file is not located then try to reinstall to another folder. Thanks again for your comment,

      Best Regards,


      • Kirk
        March 25, 2011 @ 1:02 pm


        I can now confirm that on Windows 7 64-bit, running Hydrobuddy as admin solves the problem. Right click on the hydrobuddy icon/shortcut and choose “Run as Administrator”


  • Alsagaff
    March 21, 2011 @ 5:21 pm

    Hi Daniel,
    I admire what you are doing for the Hydroponics lover that I refuse to accept not having HydroBuddy on my laptop. I purchase a new ASUS Laptop with Window 7 as i was unable to run the program on my old laptop with the Window XP.
    However, i still encounter problems after installing HydroBuddy v1.13 the difficulty.
    When i tried to start the program the following remarks appeared “Unable to open file “C:\Program Files (x86)\HydroBuddy\substances_used.dbf”.
    Press OK to ignore and risk data corruption.
    Press Cancel to kill the program.”
    when I click on OK or Cancel the program just shut down.
    I appreciate your assistance.
    Thank you in for you assistance and support.
    Best Regards

    • admin
      March 21, 2011 @ 9:51 pm

      Hi Alsagaff,

      Thank you for your comment :o) The problem here is probably related to the program’s installation. Please go to the mentioned directory and make sure the substance_used.dbf file is present. If the file is present then try to execute HydroBuddy as administrator to see if the problem is solved. If the substance_used.dbf file is not found then try uninstalling and reinstalling the program in a different folder or manually copy the dbf file from HydroBuddy’s source zip file. Please let me know if you’re able to solve the problem,

      Best Regards,


  • sue
    March 21, 2011 @ 6:07 pm

    Hi Daniel, I just found your website and downloaded Hydrbuddy and couldn’t wait to try it. I can’t open the program, keeps saying can’t find a useable init.tcl, meaning tcl wasn’t installed properly. Did the download again and same message. Any ideas why? I really want to try your program. Thanks for any help.

    • admin
      March 21, 2011 @ 9:48 pm

      Hi Sue,

      Thank you for your comment :o) I have never seen the error you mention. Please specify which operating system version you’re using and when the error is appearing so that I can help you solve it. Thanks again for your interest on HydroBuddy :o)

      Best Regards,


  • Chris
    March 28, 2011 @ 9:58 pm

    I can’t get Hydrobuddy 1.31 to install.

    I’m running XP Home (s. pack 3). When I run the installation, I get an error while it’s trying to build the uninstall. The error says: “error in action execute action. Error in install/uninstaller. Error during trunate on file 26b0520.” The error log generated from this is fairly long so I won’t post it here, but I can send you a copy of what it says if that helps. Looks like it might be a useful program.



    • admin
      March 29, 2011 @ 1:18 pm

      Hi Chris,

      Thank you for your email :o) Ok, this bug seems to be caused by the installer so I may have to remove the uninstaller in order to warrant compatibility with Windows XP machines. I will make sure this works appropriately within the next release. Thanks for helping me make the software better!

      Best Regards,


  • […] noooobs!! Thats exactly what Iam! lolol I found a nute program, looks to be pretty recent. HydroBuddy v1.31 : The First Free Open Source Hydroponic Nutrient Calculator Program Available Onlin… Pretty cool from what I can see. __________________ My First Grow – Journal – Kryptonite – […]

  • Michael
    March 30, 2011 @ 9:36 pm

    Heard great things about the Hydrobuddy from a client… downloaded but won’t open in Mac OSX 10.5.8, it just quits. Tried going in installation folder but there was no folder to go in. Any help is appreciated Daniel. Thanks Michael

    • admin
      March 30, 2011 @ 11:56 pm

      Hi Michael,

      Thank you for your comment :o) In the meantime the v1.3 installer only supports MacOS v10.6+ so you will not be able to install HydroBuddy with your current system setup. I will work on this for the next release but in the meantime there is no quick solution to the installer issue. In any case I will also make the next Windows version compatible with emulators like CrossFire so if the installer still doesn’t work you will probably be able to use it this way. I have just sent you the standalone executable which you can use to run the program on your Mac without a formal installer. I hope this solves your problem :o)

      Best Regards,


  • Robert
    April 7, 2011 @ 12:52 pm

    Hi Daniel,

    is it possible that Hydrobuddy starts with the last entries made before closing the program instead of starting with default values? I also saw a small error on the Results tab (and also on the “Detailed Per Substance”… popup): Calcium Monobasic Phosphate is Ca(H2PO4)2.H2O, not Ca(HPO4)2.H2O.

    Thank you,

    • admin
      April 7, 2011 @ 6:14 pm

      Hi Robert,

      Thank you for pointing out this error :o) It will be fixed on the next release,

      Best Regards,


  • David
    April 10, 2011 @ 1:38 pm

    Hi Daniel , Re ,Copy Commercial Formulas in HydroBuddy. The commercial product I am using lists their formula as %W/V. (ie,Nitrogen of nitrate 3.52%W/V ) Do I just list it as 3.52% ? Thanks again David.

    • admin
      April 10, 2011 @ 6:20 pm

      Hi David,

      Thank you for your comment :o) The input percentages should be W/W% so you will need to convert these values before inputting them. In order to do this simply divide the value by the density in g/mL. I will add a feature to add percentages directly as %W/V on the next version.

      Best Regards,


  • Jean-Luc
    April 12, 2011 @ 12:32 pm

    Hi David (and Daniel)!
    I remember the W/W versus W/V being a topic of a discussion in some Forum a while back. And in fact (which I didn’t realize), US and so to speak international Fertilizer regulations seem to ask for W/W always (if I remember well- except “special fertilizers), either for solid or liquid fertilizers. Eventually there was some to and fro about how to determine the density of individual products in some case. Anyway, I am curious what product (or manufacturer) has chosen to give the percentage in W/V, respectively if it really is the case? May I ask what product/manufacturer you refer to? Just out of curiosity ;-)

    • tester
      April 13, 2011 @ 12:49 pm

      Advanced Nutrient’s tech support wrote this in an e-mail:

      “For the liquid products the NPK% are listed as W/V (weight/volume) while the
      powders are listed as W/W (weight/weight.) The math is fairly similar if you
      actually carry out the calculations for 1K/1L of product.”

      Metrop lists both w/w and w/v

  • Jean-Luc
    April 14, 2011 @ 1:52 am

    Now that’s interesting tester, because that’s what I assumed in the first place. Weight of Volume is in fact the most LOGICAL way of listing liquid fertilizers. Simply look at the way the maths are made up “traditionally” (in HydroBuddy as well for instance). But with the forum discussion I mentioned earlier, I was actually outvoted (based on the fact that international fertilizer regulations strictly ASK for W/W even for liquid ferts). Once again I was right (was I?) but just sillily outvoted and my argumentation overruled. Besides, assuming a density of around 1:1.12 – 1:1.30 – the difference is as much as 12-30%! Majority may in some case just be a way to impede progress! I guess I am staying on too long with the wrong people. LOL

  • Jean-Luc
    April 14, 2011 @ 2:00 am

    @ Daniel,
    I guess that in the context of a choice of W/V vs W/W within the program it is important to find out (and make cannonproof) what the default listing for standard commercial liquid fertilizers is. Except of course if it’s variable. Why? Because most people will not be able to make a choice on their own and get confused by the two options.

  • David
    April 14, 2011 @ 6:48 am

    Hi Daniel,Jean-Luc, I hope I have not confused you but what I was refering to is that I have have a commercial concentrated A+B nutrient (Liquid) product which gives all the contents as %W/V.I just wanted to know how to copy these values into HydroBuddy so I can mix my own.My bulk fertilizers are listed as %.Thanks David. Ps in HydroBuddy Mass units grams or Ounces selection. When I go to Results after calculation . Mass still indicates grams even though the actual weights change acording to my selection.

    • tester
      April 14, 2011 @ 11:53 pm

      Would you tell us what is that product exactly?

  • Jean-Luc
    April 14, 2011 @ 7:55 am

    David, as far as I am concerned, I don’t feel confused by you or your question. This part seems confusing by itself. I also got your point and understood your question. As I translate it mathematically, HydroBody calculates ppm of Mass in Volume (i.e. % or ppm of gram contained in Liter or gallon) right? Thus with the reverse maths of any liquid when the percentage is given in %W/V, no conversion (division) by mass density would be necessary. But this is still tricky to me – please correct me if I got it all wrong ;-)

    PS: In case you need to determine density of a liquid (fertilizer), take (measure) 100 ml and weight them with a precision scale. If the weight is 114.54 gr, the density simply is 1:1.1454. Or use 1 Liter and move the point (probably even more precision)

  • Simon
    April 15, 2011 @ 10:42 am

    Hi Daniel
    I am interested in HydroBuddy but I get an error on trying to launch. After downloading the system to Windows 7 , I have the desktop icon ‘HydroBuddy’ and on clicking this I get the error message …”The procedure entry point deflateSetHeader could not be located in the dynamic link zlib1.dll” . I have no idea what it means and if this is something in my system then I can take it to a programmer to look at .. however if you think it relates to the download and that you can guide me, please let me know.
    Thank you Simon

  • Chris
    April 18, 2011 @ 7:14 am

    i couldn’t figure out where my extra iron ppm was coming from…sodium borate defaults to 7% iron.

    the autoupdate feature was stalling and preventing me from running hydrobuddy. i deleted files, reinstalled v1.13…and had some luck with disconnecting from the internet…and finally deselecting auto update. while it’s possible to get around it, can the auto update ask if you want to update? (like java and acrobat do) essentially not be so automatic…

    hydrobuddy is the best program out there :o) many thanks!

  • Charles
    April 19, 2011 @ 2:50 pm

    A) What is the procedure to add a custom salt, I am a layman to this, thank you.

    B)Please as a feature add the ability to adjust a formulations grams/ml per gallon/liter past the copy commercial formula modal, it is extremely useful for tinkering with their ratios to see their actual PPM combine this also with a tab where your numerous formulations could be displayed side by side with their titles displayed, so that one might take various commercial, or calculated formulas, display them visually side by side with their respective numerical PPM values displayed, with a summation feature that would dynamically display the individual PPM values and total values of all the constituent parts.

    I believe this feature would allow the novice and expert grower the opportunity to combine their own formulations with those commercially available in a way that will potentially save millions of dollars by avoiding nutrient deficiencies and overdoes.

    Finally, would it be possible theoretically to add amino acid, citric acid, and humic/fulvic as a chelate in the program or is that not possible? These can be used on many of the micro-nutrients avoiding the need for EDDTA or EDTA at all. As they’re harmful and actually after detaching start chelating materials from the cell walls of your plants.

  • Donald Baecker
    April 19, 2011 @ 11:36 pm

    deflateSetHeader could not be found in dynamic link librar zlib1.dll

    Thanks for your help.



  • Donald Baecker
    April 19, 2011 @ 11:43 pm

    I am using windows 7 64 bit


  • April 26, 2011 @ 7:25 am

    Hi Daniel,

    Your hydrobuddy calculator seems to be the perfect aid for my senior science project. I would like to investigate the effect of various nutrients on the growth of tomato plants. Can you suggest an experimental design? I was going to make up various solutions deficient in N, P, K, Ca or Mg. Then assess the growth of the plants for around 4 weeks. What medium would you suggest i grow them in? Sand? Potting mix?
    To simplify things, for my base solution i have chosen to use the “Tomatoes – Third Cluster (U of Florida)” throughout my experiment. Does this sound okay?
    Also, when trying to make a solution deficient in potassium, i set the nutrient to 0, but it does not give me 0 potassium nitrate grams.
    Any help or suggested further reading would be greatly appreciated,

    • admin
      April 26, 2011 @ 11:49 am

      Hi Kiran,

      Thank you for your post :o) The calculator will include potassium through a salt used to fill another element in most cases so your safest bet is simply NOT to include any salts containing the element you want to eliminate. Simply eliminate potassium nitrate from the salts you will be using. Regarding your solution choice, it is better to choose one of the generic solutions rather than this, more specialized one. Select a generic solution from the formulation list. Also remember that you need to cover genetic variability for your conclusions to have any validity, you also need to ensure that you have one separate reservoir for each plant and make sure they all have the same temperature, light and humidity conditions. You need at least 10-25 tomato plants for each element you want to study if you want to draw serious conclusions. Of course, if this is just to see the generic effects of deficiencies one plant per element and at least 3 controls will do (make sure you have more than 1 control because genetic variability may cause a single control to be a bad source of comparison). Thanks again for your post,

      Best Regards,


      PS: If you want to completely eliminate genetic variability you can grow a single plant and then use cutting from that plant to grow new ones to carry out your study. They will all have the same genome then.

  • Aaron Davis
    April 29, 2011 @ 4:13 pm

    I just downloaded this program and it seems really nice, but after closing the program after the initial startup and reopening it I get this error message

    Unable to open file “C:\Program Files\HydroBuddy\substances_used.dbf”.

    Press OK to ignore and risk data corruption.
    Press Cancel to kill the program.

    If I click either Ok or Cancel it just closes the program… Not sure whats going on here..

    • Aaron Davis
      April 29, 2011 @ 5:00 pm

      I read some of the above comments, and found the one about running the program as the administrator and it solved the problem with the used_substances.dbf file.. If I run it as administrator the program works fine

  • Jason Devine
    May 1, 2011 @ 2:46 am

    Having a problem with GTk I get this message. “The procedure entry point deflateSetHeader could not be located in the dynamic link library zlib1.dll.”
    I am running windows XP.
    Thanks for your great work.

  • Jason Devine
    May 1, 2011 @ 3:10 am

    Ok i have found a way around. If i download gtk from sourcforge and copy zlib1.dll to the hydrobuddy program folder it allows me to run the program. It is probably the rough way of fixing this but it works.

  • Ryan
    May 1, 2011 @ 12:25 pm

    OK, awesome calculator… Just a couple questions…

    When I am to copy a commercial formulation, when addition as volume is selected I have two options… Now, what do these both mean, and what should I put in the box? “Density (g/mL)” and “Volume of addition (mL)”, have got me confused… Please help!

    Also, I was trying to do a formula for a nute additive (Big Bud from AN), but I can’t do a simple mix, everything is A+B, any ideas…

    Thank you so much for a great program.

  • Jean-Luc
    May 5, 2011 @ 4:17 am

    Hi Ryan,
    1. With any attempt to reproduce commercial nutrients, you have to transcribe the GA (guaranteed analyses) from the manufacturers labeling to the program as you know. But to have the correct transcription, you absolutely need to know if the manufacturer lists the GA in mass/mass or mass/volume. After that Daniel needs to tell you what option to chose in either case. 2. Any 2 part (A+B) nutrient can only be reproduced as a 2 component nutrient. You thus have to either use the sum of the analyses and let HydroBuddy split it in A&B or let it calculate each part (A+B) separately. However, in case you want concentrates, you always have to split in A&B components, if the original product is manufactured that way. In rare cases, where specific components need to be used, to be able to have a SINGLE part (additive), you firstly need to figure out what they actually are. As some components used by HydroBuddies algorithm will not be compatible with each other, they need to be split up (in A&B) as a “logical” consequence.

  • MindzEye
    May 5, 2011 @ 12:01 pm

    Can you please include an SiO2 calculation instead of Si only in custom compounds please..

  • admin
    May 5, 2011 @ 5:32 pm

    Hello Guys,

    I have the pleasure to announce a new release of HydroBuddy :o) (v1.40) This release covers some important improvements/changes from previous versions.

    – Rolled back GTK interface for Windows, it didn’t add anything and made the program lose compatibility with emulators and generated a lot of errors on Windows 7 and XP. The program now uses the windows interface as it used before. Note that linux still uses GTK as it is the default UI on that operating system. The windows program version should now be compatible again with emulators (wine, crossfire, etc)

    – Added updater to linux version, it is an experimental feature and the program must be run as root to update (I know, not the best but working on it)

    – Added choice to add and calculate Si as Si or SiO2

    – Added independent assignations of K/K2O, P/P2O5, Si/SiO2 through dropdown menus

    – Added Commercial nutrient comparison feature (allows you to add many commercial formualtions and compare them right next to each other)

    – Added W/V and W/W% distinction on “add commercial nutrient” module

    – Fixed calcium phosphate formula

    – Fixed sodium borate iron issue (need to update your DB)

    Note that if you want to update the Databases of your mac or linux versions imply copy the substance.dbf file from a separate installation and rename it as substance_used.dbf (the program will update changes on startup while preserving your custom additions). Thank you very much for all your support!

    I hope you enjoy this release :o)

    Best Regards,


  • Jean-Luc
    May 6, 2011 @ 6:21 am

    Just tried to launch vers. 1.40 on Tiger (1.4.11) and got a prompt error message: Open failed – couldn’t open “HydroBuddy-1.40-MacOSX-install”. The good news are: CrossOver (even 8.0) installs an launches HydroBuddy-1.40.exe properly (again). Just giving feedback here. Cheers, Jean-Luc

    • admin
      May 6, 2011 @ 10:44 am

      Hi Jean-Luc,

      Thank you for your feedback :o) Sadly the Mac installer will never be compatible with anything lower than Leopard due to the way in which the installer is built. I am however glad that the Windows version returned to its emulator-compatible state :o) Thanks again for commenting,

      Best Regards,


  • […] Posted by MindzEye I have been studying my brains out about this stuff, I ended up finding the Hydro Buddy calculator, I guess it had issues when it first started but it works great now and has taken a lot […]

  • Mindzeye
    May 10, 2011 @ 5:55 pm

    Hello, Im really liking the new release!! There still is a problem with SiO2 calculations.. I added a custom compound potassium silicate… HB doesnt calculate the SiO2 and doesnt add the potassium this compound contributes.. I still have to use another calculator to get my formula right…

    • admin
      May 11, 2011 @ 1:25 am

      Hi Mindzeye,

      Thank you for your comment :o) I truly don’t see how this is the case. I just used the program to calculate a formulation based on potassium silicate and obtained adequate values for the silicate as well as its potassium contribution, you’re probably not using the program correctly. Please send me an email to dfernandezp at unal.edu.co with the detailed description of what you’re doing and I’ll help you get it right. Thanks again for commenting,

      Best Regards,


      • Mindzeye
        May 11, 2011 @ 11:51 am

        I got the support I needed… It was just the purity of my custom compound that was throwing my numbers off.. Thx for the wonderful FREE program!

  • […] etc.. But I do know of a free nutrient calculator that might be able to help figure things out. HydroBuddy v1.40 : The First Free Open Source Hydroponic Nutrient Calculator Program Available Onlin… __________________ Website Owner Home Hydroponic Systems Garmin GPS Navigation […]

  • Joe
    May 17, 2011 @ 6:00 pm

    Currently getting an error window that says missing operator between “Joe” and “Joe” when I try to save or set water quality parameters. “Joe” is the name of the water quality data I inputed.

    thank you

    • admin
      May 19, 2011 @ 10:23 am

      Hi Joe,

      The problem might be that the name was already in the DB or some other issue with this name. Simply redownload the program and reattempt this or add the quality parameters with a different name (like joe1). I hope this helps,


  • Kevin
    May 18, 2011 @ 5:43 pm

    Downloaded and installed the program with one problem. I receive the following error when trying to open the program: “Unable to open file “C:\program files (x86)\Hydrobuddy\substances_used.dbf” “Press ok to ignore and risk data corruption”, “Press cancel to kill program”. I reinstalled a fresh download and it worked fine until the message appears when trying to reopen after closing.

    I’m using Win7 64-bit. Also any plans to create a iPad version. That would be really handy.

    Thank you.

    • admin
      May 19, 2011 @ 10:23 am

      Hi Kevin,

      Thank you for your comment :o) You need to run HB as Admin on Windows 7 or run it in XP compatibility mode to eliminate this problem (created by windows using a roaming folder copy instead of the dbf file within the installation folder). Also there are no plans for an Ipad version but the source is available if you want to build one yourself (send it to me if you do so that I can add it to the website),

      Best Regards,


  • Kevin
    May 19, 2011 @ 4:15 am

    Daniel, Using “Tomato (Howard Resh)” database figures, I noticed a discrepancy referring to Dr. Resh’s book and your result when figuring for Ca. To achieve 200ppm Ca in 1 liter of water using Ca(NO3)2 (90% purity), Hydrobuddy shows 1.31 grams are needed, while Dr. Resh’s book calculates .91 grams are needed. When figuring for 100 gallons, everything except Ca was accurate. Please verify.

    Thank you.

    • admin
      May 19, 2011 @ 10:21 am

      Hi Kevin,

      HydroBuddy’s results are accurate according to whichever Calcium nitrate formula you’re using. Bear in mind that the calcium nitrate found within HydroBuddy is 100% pure calcium nitrate tetrahydrate. You should add another calcium nitrate if your source is different. HydroBuddy has been checked extensively and I guarantee the amounts calculated are correct for the calcium nitrate composition percentages and purity used. Thanks again for your comment,

      Best Regards,


      PS: I have noted Howard Resh sometimes uses anhydrous calcium nitrate in his calculations, reason why weights are reduced

  • Kevin
    May 19, 2011 @ 5:10 pm

    Daniel, Thanks for the info. I checked my supply and it looks like I have a green house grade bag of calcium consisting of 1.0 % Ammoniacal Nitrogen and 14.5% Nitrate Nitrogen. No wonder my plants are having trouble. I will search for 100% pure calcium nitrate tetrahydrate. If you know a good source, please post. Thank you again for your help.


    • admin
      May 20, 2011 @ 12:47 pm

      Hi Kevin,

      Thank you for your comment :o) there is nothing wrong with using greenhouse grade calcium nitrate as long as you take into account all percentages adequately within your formulation. Just input a custom “calcium nitrate” within HydroBuddy and use this custom addition to calculate your nutrient solutions. There is really no benefit in spending so much for the Tetrahydrate unless you absolutely need to have all absence of ammonium (note that ammonium is proved to be beneficial for at least a dozen plant species under 1:4-1:10 the amount of nitrate. Thanks again for posting,

      Best Regards,


  • Kevin
    May 20, 2011 @ 2:34 am

    Hi Daniel,

    I tried to search for the answer but didn’t find one so I will ask here, I hope this is the last one….When using Resh’s “peppers” DB, I noticed the gross error for Ca is -12.9% and S -81.5%. When you have an error like these should I try and substitute corresponding salts with one that brings the error level closer to 0% or is it better to use the specified amount since it is for a 100 gallon mix?

    Thank you.

    • admin
      May 20, 2011 @ 12:48 pm

      Hi Kevin,

      Thank you for your comment :o) An 81% error is way too high which means that you’re not obtaining the required result for the formulation you want. If you are set on having this formulation then you need to change your salts to others that have ratios which better suite the intended preparation. However it might be better to just change the formulation to another which is more in line with your salts if you do not want to purchase new ones. Thanks again for your comment,

      Best Regards,


  • Kevin
    May 20, 2011 @ 3:05 pm

    That’s what I thought. I used an unaltered db formula for an example and will make the adjustments when necessary when looking at the others. In Resh’s book he has some tables that address this issue and I will work on it.
    Thank you.

  • Kevin
    May 21, 2011 @ 1:59 am

    Hi Daniel,

    While working on various formulations, I seem to either have a gross error of either + 34% or – 67% for S. With S being the Degree of Freedom element, do I need to adjust the ppm a little high/low on the other elements to correct for it, or should I leave it as is? I have tried substituting other salts, but it seems to make things worse. Here is an example:

    N 130, P 35, K 220, Mg 45, Ca 150, S 70, Fe 1.5, Zn.15 , B .5, Mn .8, Cu .10,

    This results in an error of 33.9% for S Everything else is right on the money.


    Thank you.

    • admin
      May 22, 2011 @ 12:28 am

      Hi Kevin,

      The problem here is that your formulation does not match the ratio of S to other element on your salts. Sulfur is the degree of freedom so the program is sacrificing accuracy in S in order to reach accurate results on other salts. If you want to have completely accurate S then try changing the degree of freedom to something else related to S (possibly Mg or K) in order to see how this changes your overall formulation. Now if you want everything else to be accurate then you will need to live with the +33% error on sulfur. The best solution might be to use the combination of salts that gives you -67% and simply add sulfuric acid to get the missing sulfur. Adding sulfuric acid should allow you to get much more accurate results on a formulation were S is lacking. I hope this helps,


  • Kevin
    May 21, 2011 @ 7:19 pm

    Hi Daniel,

    Seems like I get the following pop up message each time I run a calculation on any of the Db: Example: Melons (Douglas Peckenpaugh), the message for each salt states “You have selected a fixed weight for Magnesium Sulfate(Mg). The program will find a solution with this constraint but it will add more of this substance if it will lead to a better solution.”

    Is there a setting to turn this message off? It occurs on every Data Base selection.

    Thank you.

    • admin
      May 22, 2011 @ 12:31 am

      Hi Kevin,

      The program will always pop this message if you have selected a fixed weight of any salt. If you want to remove this message simply remove the assigned weight (using the reset all weights button on the selection screen). However the message will ALWAYS be displayed if fixed weights are input as a necessary precaution.


  • Kevin
    May 24, 2011 @ 7:29 pm

    Hi Daniel,

    Thank you for your help. Everything seems to be growing/working fine and Hydrobuddy was a huge plus. The only compound I’m having trouble obtaining is Ammonium Nitrate due to restrictions. I need it for Resh’s Peppers. I have tried various substitutes but nothing seems to fill in the void for Nitrogen like Ammonium Nitrate does, it actually does a nice job. Do you know any sources that will sell to me? I have tried two of mine and each one said “no”.


    • admin
      May 24, 2011 @ 8:09 pm

      Hi Kevin,

      Thank you for your comment :o) You can easily purchase a diluted Ammonium solution and nitric acid and use them as a substitute for ammonium nitrate within your nutrient solutions. You can get the exact same effect. However be careful as both of these substances are corrosive and should only be handle in well-ventilated spaces with adequate protective gear (also never mix the sources together but add the needed quantities separately to the nutrient solution). I hope this helps!

      Best Regards,


  • Jean-Luc
    May 25, 2011 @ 7:16 am

    Hi Kevin, in case all you need is a small(er) amount of ammoniacal nitrogen, the easiest and most common substitute (actually commonly used with nutrients) would simply be Diammonium phosphate or mono-ammonium phosphate ( aka MAP & DAP). They obviously will provide P as well, but that’s not a problem in most cases. They should still be available as well and are much less corrosive. Common ammonium nitrate is (was) only preferred because it formerly was freely available and used to be very cheap (much cheaper than MAP or DAP). About the previous “problem” with the lack of S in Resh’s recipe: the relatively high S content is simply due to the combination of magnesium sulphate and a rather high amount of potassium sulphate in the recipe. The latter is actually needed to reach the high P to N ratio. Thus the high S content in this recipe is NOT actually required but a simple consequence of the used amount of potassium sulphate . In one sentence: much less S is perfectly fine, even preferable. Cheers, J-L

  • Kevin
    May 26, 2011 @ 6:44 pm

    Thank you both for the help. I actually tried placing ammonium sulfate and nitric acid into the substance field and it showed very favorable results also. Daniel do you plan on adding a forum so information can be shared? I’m currently planting Tomato’s, Edamame, Melons, Eggplant, Sweet peppers, and Strawberries using the formulations derived from Hydrobuddy and other sources. It would be interesting to note the success/techniques of others.

  • carl mberly
    May 29, 2011 @ 5:05 pm

    To use your program on a PowerBook G4 10.4,do you know of any info/location that would help me install Hydrobuddy 1.4? It is on my desktop, when i click on the install it opens Terminal.Iam lost.I do not understand what (browse to the installation folders to execute in mac/linux) means! Any help would be greatly appreciated. Thanks

  • Kristoffer
    May 30, 2011 @ 9:18 pm


    I’m getting some errors/bugs when using the Data Log.

    When I try to Remove selected data point:

    Index Out of Range Cell [Col=0 Row=1246068]

    I can either kill the program or risk corruption of data. Either way, when I try to add a point to the data set, I’m told A data set must be selected or created.

    If I press delete while having the name of the data set marked, I get an error: Out of bounds.

    When pressing around the program just crashes. Happens every time.

  • Ajay
    June 5, 2011 @ 2:00 pm

    Hi Daniel:
    I am a greethumb – just getting my feet wet in Hydroponics. I stumbled upon your site thru fellow bloggers. It is too technical for novices like me. But i am writing this for something else.
    Words cant explain the gratitude we guys owe you. Just putting up your years of experience/expertise for the world to see/use – gratis!. I salute you – and your ilk. May your tribe grow. God Bless!

  • Cesar
    June 6, 2011 @ 4:32 am

    hey Daniel!

    I seem to be having some problems running your calculator program… every time I install it it runs fine, but when I close it and try to open it for the second time, an error message appears saying it is unable to open “C:\Program Files\HydroBuddy\substances_used.dbf”
    I would really use some help!

    p.s. I’m trying to run it on a windows 7 home basic pc :=) cheers!

    • admin
      June 6, 2011 @ 10:57 pm

      Hi Cesar,

      Thank you for commenting :o) You should run it as administrator (right click the executable, go to properties, check run as administrator, apply). This fixes the problem,

      Best Regards,


  • […] Source Hydroponic Nutrient Calculator Program Hey guys. I thought this looks pretty interesting. HydroBuddy v1.40 : The First Free Open Source Hydroponic Nutrient Calculator Program Available Onlin… From the description: "A totally free and opensource nutrient calculator for hydroponics and […]

  • suavi
    June 8, 2011 @ 11:09 am

    @Daniel Fernandez
    Do you have a twitter account? If not, will you sign up for an Account?
    Why am I asking this question? Cause I think that following your site maybe more easily by bird. :)

    On the other hand, thank you so much for this great program and effort. I will be donate when I will see and eat my first strawberry plants in this summer. :)

  • Kirk
    June 13, 2011 @ 6:23 pm

    Calcium Nitrate Tetrahydrate vs Yara Calcium Nitrate

    When we swap out Calcium Nitrate Tetrahydrate and replace with Yara Calcium Nitrate, we see a significant reduction in the amount of Ca Nitrate used (as much as 12% depending on the formulation). Why is this?

    Is the ‘Yara’ brand of Calcium Nitrate fully ‘anhydrous’?
    Or is there another reason?


    • admin
      June 14, 2011 @ 1:11 am

      Hi Kirk,

      Thank you for your comment :o) The difference arises because the Yara calcium nitrate is not really calcium nitrate but a double salt which would be better described as calcium ammonium nitrate. Therefore the proportions change and the calculations give different results. Please checkout the percentage composition values of each salt by simply editing them within HydroBuddy. Thanks again for commenting,

      Best Regards,


  • June 15, 2011 @ 9:58 pm

    I’ve downloaded the program for use on windowss vista. I made a donation first time seeing program. My question, isthere anyway to print results to take to workig table for measurring the weights of salts.

    Best regards,


    • admin
      June 15, 2011 @ 10:30 pm

      Hello Gary,

      Thank you for your comment :o) There is no way to print the information directly from the program at the moment but you can export the information to a CSV which you can then open using excel (or any spreadsheet program) to print. Thanks again for posting!

      Best Regards,


  • mohammad
    June 19, 2011 @ 6:36 am

    tanx for this perfect software
    I’am from iran
    I writen same software too
    plesae contact with me

  • Dave
    June 20, 2011 @ 5:15 am

    Hi Daniel

    I have had a look at your program and used it, a very well put together program. However when I try to reopen the program after logging off I get the following:

    Unable to open file “C:\Program Files\HydroBuddy\substances_used.dbf”
    Press OK to ignore and risk data corruption.
    Press Cancel to kill the program.

    Is there a fix for this Bug?


    • admin
      June 20, 2011 @ 1:07 pm

      Please read previous comments about this problem

  • redshirt
    June 27, 2011 @ 2:18 am

    Hi. I love the program and so far it seems to be functioning well for me.

    I have a similar problem with the availability of ammonium nitrate. I know nothing of chemistry so I’m not sure if the following components could be safely mixed and was wondering what procedure you would suggest to do so:

    Mono Ammonium Phosphate, Calcium Nitrate (Tetrahydrate), Magnesium Nitrate (Hexahydrate), Potassium Nitrate, Ammonium Nitrate (in the form of Nitric Acid and Ammonium Sulfate as you suggest), Phosphoric Acid (52%).

    Basically I don’t know the best way to combine these without causing damage or some kind of other unwelcome result. Can I just take 50% of the water volume and add everything in as you suggest in the program? Will the use of the 2 acids be a problem?

    Also some bugs I’ve noticed:

    1) in the “Result” page the “Mass” column always lists “(g)” as the unit of measurement even if you’ve selected Ounces on the “Main Page.” This can be very confusing. The numbers seem to change to the correct ones but the units don’t display properly and that could be a big problem for someone if they don’t notice.

    2) A lot of the tab orders are off in the forms. It looks like you went back and added some (like “Mn” and “N(NH4+)” on the “Main” page). It would be smoother if those were all brought into order.

    I’m not sure how much help you are willing/able to provide but if you’re interested the above ingredients are meant to give me a 9-3-6 liquid fertilizer with Ca and Mg. I copied the formula from Dyna-Gro’s “Foliage Pro” minus the micro nutrients for which I will use a commercial formula.

    I believe this requires me to use the Nitrates to keep everything (mostly) in solution. The foliage pro had a tiny bit of precipitation that went away with shaking and I assume this will do the same.

    Nitric acid seems almost as hard to come by where I am as ammonium nitrate is – do you have any suggestions?

    Thanks! Great program! Hopefully it will save me from having to pay 60$ a gallon for 9-3-6 with Ca and Mg.

  • redshirt
    June 27, 2011 @ 2:24 am

    That’s odd.

    When I run the calculation with Ammonium Nitrate it works great and I have 0% gross errors.

    When I swap out Ammonium Nitrate and add in Nitric Acid (30%) and Ammonium Sulfate (which I thought was the way I could emulate Ammonium Nitrate?) the software tells me that Phosphoric acid (52%) is no longer needed and tells me to leave it out.

    However then the gross error on Phosphorus goes up to ~20%. Is this because we can’t mix the 2 acids? Or is something else going on?

    I have S as the degree of freedom and that’s the only new element that should have been added when I swapped out the ammonium nitrate for the nitric+ammonium sulfate…?

    Very confused

  • David
    June 29, 2011 @ 11:24 am

    Daniel,Program looks great, but being a novice I need help. I wish to copy a commercial formula. I copy all the chemicals VW% of the commercial nutrient into the Copy to Commercial Nutrient Formulation window. I then hit Calculate Formulation . It then returns to the Main window but no sign of the formula.In Add Product for comparison window ,nil results. Please help.

  • […] for growing tomato's from the University of Arizona Nutrition Here is a free nutrient calculator Nutrient Calculator Although I haven't read them yet, here are a couple of books on my list to get Hydroponic […]

  • Fred Kemps
    July 3, 2011 @ 1:13 pm

    Gidday Daniel!
    I also have a problem reopening your calculator. I tried to do what you previously suggested but cannot find the right tabs. I have vista!
    Hope to enjoy your calculator like everyone else has

  • redshirt
    July 7, 2011 @ 8:29 pm

    Another note: if you use apostrophes anywhere in the program it will fail. I suppose the database is using ‘ as a separator.

    It would nice if you could encode the ‘ characters or use a different separator so that things like “Peter’s Professional” products and etc don’t crash program if I forget and accidentally put a ‘ in there.

  • redshirt
    July 10, 2011 @ 3:08 am

    Sorry. Still more feedback:

    It would be nice to be able to lock in certain levels of chemical components. In the formula I’m attempting to replicate I can tell I will need X amount of an acid to get to the required pH but HydroBuddy wants to use less of the acid and more of the salt with the same element. I’m sure there are multiple solutions and I’d like to use the one with the higher acid content.

    In addition to locking in certain values for substances it would be great to be able to put min and max values on the levels of substances. A number of MSDS sheets say things like “< 6% Monoammonium Phosphate" and it would be great if we could add that upper limit in order to properly replicate or closer approximate the formulas.

    • admin
      July 10, 2011 @ 12:10 pm

      Hi RedShirt,

      Thank you for your feedback :o) The option to add certain quantities of fixed chemicals is already implemented (use the set weight feature in the substances form to set a fixed amount of a given chemical substance).

      Best Regards,


  • David
    July 12, 2011 @ 4:56 am

    Daniel I wish to mix 1 liter A+B, Tomato (Howard Resh) from db. When I go Calculate using Mass grams, and then in Results I am told I will need 141.7 grams of Calcium Nitrate. Then if I go back and do the calculation in Mass ounces I am told I need 4017.127 grams of Calcium Nitrate. What is the correct result to use ? Thanks David.

  • David
    July 12, 2011 @ 12:36 pm

    Hi Daniel ,David again.I uninstalled Hydrobuddy then downloaded and installed it again. Presto, it now calculates correctly.In the results the Mass still indicates grams even if you change the Mass units to ounces. Great program,thanks.

  • David
    July 16, 2011 @ 12:09 pm

    Daniel,Could you please recommend a nutrient formula from the database most suitable to cover the three following vegis,Lettuice Coliflower and Cabbage ?. Also,is it possible to determine when to replace the nutrient by the EC value? If so at X % Thanks again,David.

  • spurr
    July 18, 2011 @ 9:16 pm

    Hello Daniel,

    Firstly, thanks for your work on this application! I have yet to dig into HydroBuddy, I was waiting for the update you wrote was to be released on July 6th, re: “Hydrobuddy’s next update will be released on Jul-06”. When will the update from v1.40 be released?

    I have the full version of Nutron 2000 software (http://www.suntec.co.nz/), current version, and I would be willing to send you the install CD and booklet if you wish to check it out. I paid for the software and it’s not installed on my boxes, so it’s not copyright infringement. So far, from reading about your application and it’s features, I see it’s better than Nutron 2000.

    • admin
      July 19, 2011 @ 3:46 am

      Hello Spurr,

      Thank you for posting :o)

      Firstly, thanks for your work on this application! I have yet to dig into HydroBuddy, I was waiting for the update you wrote was to be released on July 6th, re: “Hydrobuddy’s next update will be released on Jul-06″. When will the update from v1.40 be released?

      I don’t know when the next update might be released as I am currently very busy with other projects (probably August/September but that would only be a guess). HydroBuddy is developed on my free time (as it is an open source free project) so I only make developments whenever my work on other projects is low.

      I have the full version of Nutron 2000 software (http://www.suntec.co.nz/), current version, and I would be willing to send you the install CD and booklet if you wish to check it out. I paid for the software and it’s not installed on my boxes, so it’s not copyright infringement. So far, from reading about your application and it’s features, I see it’s better than Nutron 2000.

      I also have it and part of this is the reason why I coded HydroBuddy, I needed a truly robust piece of software that was able to do truly dynamic calculations and Nutron (and all the other commercial implementations I could find for hydroponic software) simply did not achieve this result. I developed Hydrobuddy with the idea of making the best software out there for hydroponic calculations so hopefully I am achieving this goal :o)

      Thanks again for posting,

      Best Regards,


  • spurr
    July 18, 2011 @ 9:51 pm

    Hi again Daniel,

    I have a couple of feature requests pertaining to v1.40, these may have been addressed in the soon to come update of Hydrobuddy:

    1) Can you please make the Hydrobuddy window re-sizable, ex., make the ‘maximize’ button use full screen setting? And the ability to drag the window to custom size(s) would be great.

    2) In the “Substance Selection” window, could you offer the choice to ‘select all’ or ‘delete all’, ex., delete all default salts under “Substances Used for Calculations”.

    • admin
      July 19, 2011 @ 3:49 am

      Hi Spurr,

      1) I cannot implement this since Lazarus (the programming software I use) currently has a bug around dynamic scrolling and window resizing. I will implement this once they fix the problem but it may be years before this happens.

      2) This is already on the feature request for the next release,

      Best Regards,


  • spurr
    July 18, 2011 @ 11:16 pm

    Okay, last request for now, I promise! :-)

    In the Windows installer, could you please offer the option to install for ‘all users’? I ask for this because one should use Windows from a Guest account for security purposes; and as of Hydrobuddy v1.40 there is no shortcut placed in the Guest start menu.

    It wouldn’t be a big deal for me because I could simply make a shortcut from the .exe in /Program Files/ to Guest Desktop and launch as administrator, however, my admin account has a long and hard passphrase I’d rather not type often. If I run Hydrobuddy .exe from Guest account via. /Program Files/ I get a ‘can’t access’ error from HydroBuddy for “substances_used.dbf”.

    • admin
      July 19, 2011 @ 3:52 am

      Hi Spurr,

      The installer generator I use doesn’t have this option but I’ll look for some solution to the problem. However most probably this will remain like this for the next few releases (probably at least for the next 6 months),


  • spurr
    July 20, 2011 @ 8:48 pm

    Hello Daniel,

    Thanks for your responses, that all made sense. So far I am very impressed with HydroBuddy, it’s feature packed and pretty bug free (at least that I have found).

    I will be donating at least $100 to you soon, hopefully that will be on a monthly basis (or maybe even bi-monthly). I want to help buy you beer and/or coffee, so you can continue working on HydroBuddy :-). Do you accept anonymous donations? (I don’t use Paypal, etc.).

    I do have another feature request, and two questions …

    a) Can you please add boxes for heavy metals and such, to the ‘add custom’ and ‘edit values’ windows (for database of substances)? I like to use Washington State and Oregon State (USA) testing of heavy metals and other impurities, in commercial fertilizers, and salt compounds, when qualifying and quantifying my formulas. Ex., could you add boxes for Ni, Co, Pb, Cd, Hg, As and Se? (maybe under an ‘advanced’ tab?)

    b) Can one set a target EC, within HydroBuddy, so that a pre-defined formula (via. stock solution) is adjusted in terms of mL per liter of working solution (fertigation water)? (I hope that question made sense, if not, I can elaborate)

    c) In the window “Nutrient Ratios”, can one add custom ratio(s) of only two elements? If so, how? I tried clicking the “Add Custom Ratio” button but it only offers relativity of three elements (ex., N-P-K).

    As an addendum: is not the use of the term “ratio” with respect to more than two elements inaccurate? That is, a ratio must be two elements (i.e., X/Y = ratio of X to Y), not three. To my understanding, three elements do not a ratio make, am I incorrect?

    From a few academic resources (ex., UC Davis), to find N-P-K or K-Ca-Mg (what is sometimes referred to as a ratio), one would do the following:

    for example:
    N = ppm of total N (ammonicial + nitrate)
    P = ppm of P
    K = ppm of K
    L = element with lowest ppm; in this case let “L” represent ppm of P.

    N = 150 ppm
    P = 50 ppm
    K = 200 ppm
    L = 50 ppm

    N/L = 3
    P/L = 1
    K/L = 4

    Thus, the relativity of N-P-K by ppm is 3-1-4.

    P.S. where I can find your e-mail address, for private communications?

    • admin
      July 21, 2011 @ 7:28 pm

      Hi Spurr,

      Thank you for your comments :o) I am glad you like HydroBuddy and have found it to be bug-free (for the most part). I will now answer what you have said :

      – if you want to make a donation without using paypal you could send it through western union. Any donation is obviously very appreciated to support the development of this software :o)

      a) In my mind this makes no practical sense as having boxes for these nutrients is futile as the uncertainty you have in their concentrations is extremely high simply due to the impurities found on your other salts. It makes no sense to make a calculation that will tell you that you have 0.00001 ppm of mercury if you have an uncertainty of +/-0.001ppm simply because of the salts you’re using (a salt with a 0.1% impurity might introduce a +/-0.0001 uncertainty in most minor elements). Making such calculations would only make sense if the person used very pure salts (meaning analytical grade) or had extremely accurate water and analysis of all of their used minerals and this is simply not the case for the incredibly large majority of users. It therefore simply makes no sense to do all the effort that is required to do this as its practical usefulness is none.

      b) No this is not implemented.

      c) Yes, use the drop-down boxes above the buttons to select the different elements on the ratios.

      A ratio is simply a relationship between two or more values. A ratio between three values A:B:C is simply a way of showing A:B, A:C, B:A and B:C in a condensed and easy to understand manner.

      Thanks again for your comments,

      Best Regards,


      PS: My email is dfernandezp@unal.edu.co

  • spurr
    July 21, 2011 @ 7:01 pm

    Hey Daniel,

    I think I found an error in Hydrobuddy’s conversion of SiO2 into Si. We know that SiO2 has 46.74% Si (by molar mass), thus a potassium silicate product with 7.5% SiO2 has 3.5055% Si (being that 7.5*0.4674 = 3.5055). However, HydroBuddy converts 7.5% SiO2 into 3.513% Si.

    P.S. I have noticed a few bugs while working with Hydrobuddy, ex., if I change Fe from 2 ppm to 3 ppm, HydroBuddy tells me I don’t need MKP or KNO3 any longer, however, MKP and KNO3 have no Fe. That bug appears when I work my custom mix for medical C.sativa L., as follows:

    (it’s late here, so I’ll double check this in the morning)

    Pennington Epsom salt = 44.574 grams
    Peter’s Pro. Hydro-Sol = 66.659 grams
    mono ammonium phosphate = 1.936 grams
    mono potassium phosphate = 5.619 grams
    magnesium nitrate = 2.271 grams
    manganese sulfate = 0.205 grams
    zinc sulfate = 0.196 grams
    YaraLiva Calcinit = 69.474 grams
    copper sulfate = 0.079 grams
    potassium nitrate = 2.992 grams
    Silo-Tec = 93.53 mL
    boric acid = 0.095 grams

    Gives an approx. EC of 1.6 mS/cm, and a ppm profile of:

    total N (ammonicial + nitrate) = 150 ppm
    NO3 = 140 ppm
    NH4 = 10 ppm
    P = 50 ppm
    K = 200 ppm
    Ca = 132 ppm
    Mg = 66.5 ppm
    S = ~70-80 ppm
    Si = 40 ppm
    Fe = 2 ppm
    Mn = 1 ppm
    B = 0.5 ppm
    Zn = 0.75 ppm
    Cu = 0.3 ppm
    Mo = 0.067 ppm

    The above has N-K-P relativity (by ppm) of 3-1-4, and K-Ca-Mg relativity (by ppm) of 3-2-1.

    Cheers! :-)

    • admin
      July 21, 2011 @ 7:34 pm

      Hi Spurr,

      Thank you for your comments :o)

      – I will check the Si discrepancy you mentioned but most probably it is related to some rounding issues.

      – The Fe thing is not a bug but simply the result of the linear equation solver, probably after you make a small change in Fe the linear equation solver is not able to find a satisfactory solution to the problem. All variables are correlated for the solver so any change in an element affects all salts (even if they do not contain it) in some way from a mathematical perspective when doing the matrix solving procedure. Even if in the end MKP and KNO3 do not contribute with Fe when you raise Fe the solver is not able to find a solution. It would be best to reformulate the mixture or use another degree of freedom to solve.

      Thanks again for writing,

      Best Regards,


  • spurr
    July 21, 2011 @ 7:05 pm


    The above fertilizer solution is an example of direct addition to 100 liters.

  • spurr
    July 21, 2011 @ 8:23 pm

    Hello Daniel,

    Thanks for the answers and comments.

    > Daniel wrote:
    >> Spurr wrote:
    >> C) In the window “Nutrient Ratios”, can one add custom ratio(s) of only two
    >> elements? If so, how? I tried clicking the “Add Custom Ratio” button but it
    >> only offers relativity of three elements (ex., N-P-K).
    > c) Yes, use the drop-down boxes above the buttons to select the different
    > elements on the ratios.

    I tried using the drop-down selection, but it only allows for three elements, not two. In each drop-down down box there is no option for ‘none’, one has to choose an elmeent for all three drop-down boxes. Ex., if I select NO3 for the first box and S for the second box, and don’t edit the third box, HydroBuddy gives me ‘ratio’ of NO3:S:P2O5.

    > Daniel wrote:
    > … It would be best to reformulate the mixture or use another degree of
    > freedom to solve.

    I recall reading a blog post of yours about how to adjust the degree of freedom, not by element but by percent, or am I imagining such a blog post? I can’t seem to find it again. I have messed around with using elements other than S, for degree of freedom.

    Thank again, I can’t relate how impressed I am with your work. And the fact your not a computer scientist makes it all that more impressive. Thank you so much for freely sharing your work, and making it open-source. I am staring to study C++ and Java, as a minor of my plant physiology major. If in the future I can help in any way with hacking HydroBuddy, let me know :-)

    • admin
      July 22, 2011 @ 9:56 am

      Hi Spurr,

      Thank you for your comments and kind words about HydroBuddy :o)

      I tried using the drop-down selection, but it only allows for three elements, not two. In each drop-down down box there is no option for ‘none’, one has to choose an elmeent for all three drop-down boxes. Ex., if I select NO3 for the first box and S for the second box, and don’t edit the third box, HydroBuddy gives me ‘ratio’ of NO3:S:P2O5.

      Yes, you have to select three but if you just want the information from two then simply ignore the third. The three nutrient ratio A:B:C implicitely includes A:B so just don’t look at the third one if you don’t need this information.

      I recall reading a blog post of yours about how to adjust the degree of freedom, not by element but by percent, or am I imagining such a blog post? I can’t seem to find it again. I have messed around with using elements other than S, for degree of freedom.

      The degree of freedom doesn’t have any “percentage” it is just an element choice.

      By the way HydroBuddy is programed in FreePascal (using Lazarus) which is a very easy to learn language so you’re definitely welcome to look at the source and better understand how the program works. I am glad you’re enjoying the program :o)

      Best Regards,


  • Joe
    July 22, 2011 @ 12:00 am

    Hi Daniel,
    love how the program is growing.
    what is the easy way of backing up the data,
    I have it on my laptop and office computer and would like to sinc the databases so the work done on one shows up on the other.
    any help would be great.

    • admin
      July 22, 2011 @ 9:54 am

      Hi Joe,

      Thank you for your post :o) If you want to copy databases simply copy the .dfb files to your other computer (this is where all relevant information is kept). Thanks again for writing,

      Best Regards,


  • Omar
    July 23, 2011 @ 10:11 am

    Hello Daniel,

    I want to thank you for your efforts. I am from Lebanon (Middle East)and will be trying some hydroponic lettuce shortly. I was wondering if you had any suggestion for the nutrient solution.

    Thanks again,
    Hydrobuddy is a major help

  • Joe M
    July 24, 2011 @ 7:28 pm

    Hello Daniel
    I just discovered your program and think you did a fabulous job. I think the program runs very smoothly and you hard work is evident. Its ability to find the right amounts of chemicals to create a balance is amazing. I plan to use it to support my aquaponic set up. There are certain nutrients which are not in the fish poop so may have to be added at times.

    After selecting the chemicals that give you the desired ppms, it would be nice to be able to name and save the list of ingredients for later use. Reading threw you blog, I thought that it did it, but I couldnt figure out how.

    One other thing which must be percular to my computer is that when openning hydrobuddy after installation it works fine then the second time I try to open it, I get an error message
    “unable to open file C:\Program Files (x86\ HydroBuddy\substances_used.dbf”

    The file is there, but seems like it is corrupted.

    I am using Windows 7 64 bit and I use open office (which might be relevant because it would open the dbf file.

    Any way thanks for your efforts.

    Joe M

    • admin
      July 24, 2011 @ 8:38 pm

      Hi joe,

      Thank you for your comment :o) I am glad you like HydroBuddy! Please read through the comments to find the solutions to your issues (already reported and solved before),

      Best regards,


  • […] Look at this link, you will find all you need: click Here […]

  • Joe M
    July 29, 2011 @ 2:26 am

    Hello Daniel

    Running as Administrator solved my problem (unable to open file C:\Program Files (x86\ HydroBuddy\substances_used.dbf”

    1) On the Results page, the Mass indicates “g” even though the Mass Units have ounce selected. Calulation is correct -just shows g in stead of oz.

    2)Also, A nice feature might be having the abilityto name and save the Substances Used for Calculations so you can have different groups of nutrients for diferent purposes (Since it takes some tweaking to figure out which combination give you enough of this but not too much of that).

    Your program is giving me some good insights.

  • July 29, 2011 @ 4:14 pm

    Daniel, could you email me through my website? (www.otokehort.com) It would much appreciated!

    Kurt at Otoke horticulture

  • Roy
    August 16, 2011 @ 12:08 pm


    This is awesome software! I have tweeted about this software.

    To check your solution, perhaps think about using our multi-ion meter, measure 6 ions at once with one probe!

    Demo video on (commercial links not permitted)


  • mac mcneil
    August 17, 2011 @ 2:02 am

    great program, but why does it only load the first and fails to open after closing the first time. This happens on Win7 Home Premium, 64bit and 32 bit, and Ubuntu 10.10

    • admin
      August 17, 2011 @ 4:23 am

      Please read the above comments where this issue is already discussed and solved

  • Charles
    August 24, 2011 @ 9:28 pm

    Hope you’re well, it’s August and no update, I’m not here to complain as I know this is free software developed out of a passion and I’m used to the delays without deadlines scenario, but I worry for the project as a whole, I see so much potential in this for the more advanced growers, that would like to tailor solutions to plants instead of the other way around, well best of wishes.

  • Chris
    August 31, 2011 @ 5:31 pm

    Hello Daniel!

    i have a certain micro nutrient profile that i like to use. it contains 0.05% iron (we’ll just focus on one element for now). I have a grow formula (4-2-5) and a bloom formula (2-5-6). I adjust the predicted EC of both to 2.0. My issue is that the grow formula has 2.4 ppm iron, and the bloom formula has 3.8 ppm iron. Why is this? Should the iron ppm in both formulas be the same?

    I just tried playing with the Data log. I input a couple of arbitrary values, hit ‘analyze data’ and hydrobuddy crashed.

    I’ve been studying the Mulder chart. Does Calcium affect some elements more strongly than others? What are the important ratios, and how do you manipulate them? Is there a process? Are there ideal ratios (e.g. K/N) or can you find homeostasis at different ratios? That is, are there multiple ratios at which plants will be healthy? How much do ratios matter? Some people have said that plants will take what they want from solution, and a 5-5-5 will work equally as well as a 2-1-2. What are your thoughts?


  • Chris
    September 2, 2011 @ 3:43 am

    I’ve been trying to copy General Hydroponic’s Floranova Grow using their listed ingredients. Its NPK is 7-4-10 with 4% Ca, 1.5% Mg and 0.1% Fe. FNG weighs 1.41 kg for a 946 ml bottle – 1.49 g/ml.

    Ammonium Molybdate, Ammonium
    Phosphate, Calcium Nitrate, Cobalt Sulfate, Copper
    Sulfate, Iron DTPA, Magnesium Sulfate, Manganese
    Sulfate, Potassium Borate, Potassium Nitrate,
    Potassium Phosphate and Zinc Sulfate

    not only can I not get close, and aside from the ingredients not in your database, but ‘substance ammonium phosphate is not compatible with concentrated solutions.’ Is this a case of GH trying to confuse would be copiers?

    using MKP, KNO3, Ca(NO3)2, and HNO3 it comes out perfect. My concern is the 80 g of nitric acid per litre of stock solution. Is there any problem using this much nitric acid? What will the pH of the final nute solution be? I want my pH at 1.86 EC to be ~5.8. 80 g of 38% nitric acid in 1L of stock solution is about 0.5 mol, and in 100L of solution pH will be 2.3?

  • John
    September 3, 2011 @ 5:13 am

    I get the below message when trying to open version 1.4

    unable to open file …… substancespused.dbf

    When I hit the cancel button or ignore button the program crashes. It looks like a really nice program and I’d like to use it but can’t



    • admin
      September 4, 2011 @ 11:26 pm


  • Dean
    September 4, 2011 @ 5:28 pm

    It would be very helpful if the database was preloaded with the most common, “off the shelf”, nutrients.
    For example, I use Advanced Nutients, Sensi Grow, part A & B and some B52 ect.
    Or can someone share their data base C:\Program Files\HydroBuddy\substances.dbf is where it is most likely stored.
    Thank you for this program. Once I figure it out fully, it will be very helpful.

  • […] of a commercial product you have the weight of, then you need to be checking out hydrobuddy, http://scienceinhydroponics.com/2011…program-o.html. I was using Lucas of the Lucas Formula's mentor's creation, who is named pH who really created […]

  • Charles
    September 8, 2011 @ 12:18 am

    If you can’t copy the formula it’s usually a problem of the ingredient they’re using is not in the formula database source list, you can however look up these ingredients by guess work, enter their formulas and their specific weights and then have it approximate it. Honestly you shouldn’t be trying to copy their formulas, they make a lot of mistakes especially trying to go universal for all plants, tailoring to your crop if you can would be better, otherwise a good general formula would be fantastic, I’d be interested in seeing someones organic product getting a guaranteed analysis performed so you could use this to calculate out how much to add in grams to a volume. Of all substances, kelp, gauno,

  • Brian
    September 11, 2011 @ 8:23 am

    First – thanks for a great program. Well done.
    Second – I farm in South Africa, using borehole water to supply the nutrients. The water has an EC of 1310uS/cm. Is there a way to enter the water EC so it is included in the calculations? Your program calculates the EC, from added salts, so do I add my water EC to the calculated result, or can the program do it for me?

    Thanks again for a program that actually works. Your generosity in offering it in the public domain is sincerely appreciated.

  • […] this out http://scienceinhydroponics.com/2011…program-o.html You can enter in the exact amounts of each element for all your products. Then you tell it the […]

  • Kadleth
    September 24, 2011 @ 7:36 pm

    This attempt of yours offers a big service to the hydro community.

    However, can you compile for OS X 10.5 Leopard & not only for 10.6 Snow Leopard?

  • Kadleth
    September 26, 2011 @ 4:12 am

    Found a way to test the app. You’ve done quite a job Daniel. Do you still dedicate time to the development of hydro buddy?

    Why not add a feature to indicate which salts are solids & which are liquid? Dissolved solid nutrients increase the risk of obstructing finer nozzles.

    Also an indication of which ions can be directly absorbed by roots & which require additional changes to become edible to plants. For example ammonium that needs bacteria to transform it, something hardly taking place when soilless.

    Cheers & hope you keep this work further.

  • Cesar
    October 4, 2011 @ 9:28 pm


    I downloaded the Windows version of hydrobuddy, everything works fine the first time i use it after the installation, but every other time I try to open the application, I keep getting this error message having to do with the substance database. I use Windows 7, could you please help me out?

    Thanks! :)

    • admin
      October 5, 2011 @ 7:39 pm

      PLEASE READ THE COMMENTS BEFORE POSTING PROBLEMS (this issue has been answered many times)

  • Mr Saunders
    October 4, 2011 @ 11:56 pm

    Fine work for the masses. Thank you, here is 10 bucks! Can you make it work for my smart phone? :)

    Maybe include some more premix formulas? P2O5 at different percentages? Give us lots of things to choose from to slide over in the substance area. Anyway, this is exactly what I needed to help grow my garden. You have my hard earend dollars to prove it! Bravo!

    • admin
      October 5, 2011 @ 7:45 pm

      Hi Mr.Saunders,

      Thank you very much for your donation :o) Sadly there are no plans to port HydroBuddy to any smartphone OS so most probably there won’t be any ports. There are some formulations available which you can access through the formulation drop down menu (you can then tweak them as you wish). Thanks again for supporting my efforts!

      Best Regards,


  • […] converted to ppm ratios. To find actual values use this amazing calculator called HydroBuddy: http://scienceinhydroponics.com/2011…program-o.html Liquid nutrient NPK analyses must be put through a complex calculator accounting for density to […]

  • October 26, 2011 @ 2:07 pm

    Thanks for great program ….Have question what conwersion factor are you using for ppm .70 factor scale ..or .50 factor scale

    • admin
      October 28, 2011 @ 4:33 am

      In this program ppm are always mg/L not to be confused with a “ppm” measurement which is a conversion from conductivity used in TDS analysis (which is NOT used at all in HydroBuddy). There are NO conversions regarding ppm values in Hydrobuddy as the ppm (as I just said) are a concentration measurement taken as mg/L. Please read more about concentration measurements.

  • October 27, 2011 @ 4:24 pm


    I am writing an article for a magazine about software for hydroponics applications. I’d like to ask you a few questions if you can find the time. Use the email address I provided and let me know as soon as you can. After that you can delete this comment is you wish, I just saw no other way to contact you. I am in kind of a time crunch so the sooner the better.



  • S.Giri Kumar
    November 1, 2011 @ 6:35 am


    Can you provide your mail id.




  • Alessar
    November 2, 2011 @ 3:15 pm

    Good afternoon, Daniel! I apologize in advance for my English, I use a translator. I have a question on the use of this excellent software. I added my base fertilizer Solupotasse (K2O-50, 5%; SO3-46, 6%). I counted the concentration of 1 gram per 1 liter fertilizer. APM 420 +180 (K + S), EC – 1,1 -, these values ​​gave me a program. After that I threw up in RO water, fertilizer (0 PPM), made the measurement. The result – 1.75 EC and 1225 TDS (0.7) I tried to do the same with other fertilizers, in the instructions it says that the EC should be 1.06, and showed me the same instrument, but your program says that there should be EC – 0.8.
    In what may be the problem? Explain to me please. THX! With respect from Ukraine!

  • Bruce Smith
    November 22, 2011 @ 5:56 am

    1st things first. Your calculator is the shiz nit! I love it! You did a terrific job. I do have a question for you please. Is P2O5 better for horticulture then H3PO4? Most fertilizer states the amount of phosphoric acid in the P2O5 form. Please tell me the difference between the 2 compounds. I can’t find any quality info online about this. Is it true that P2O5 + H2O = H3PO4? So I could use H3PO4 85% phosphoroic acid, but use less of it then 52% P2O5? I’m wondering if I can use H3PO4 85% food grade phosphoric acid instead of P2O5 basically? If so how do I change the %’s properly so I don’t over use the H3PO4? I would really appreciate the advice from a professional chemist.
    Thanks for your time Daniel!

    Oh, is it possible to make a new option for the software to be able to make supplements like Cal-Mag mixes or a bloom boost formula? The software want to complete a full nutrient formula. So it keeps asking for more compounds to be added to the formula to complete it. It would be nice to have that option on the program.
    Thanks again for the program you created! :)

    • admin
      November 24, 2011 @ 9:20 am

      Hi Bruce,

      Thank you for posting :o) Fertilizers do NOT contain P2O5, this is just the way to report the P concentration. Bear in mind that there are ways in which things are reported that do not necessarily match what is exactly present in the solution. Phosphorous is present as phosphate species (derived from H3PO4) on ALL commercial fertilizers but the concentration is reported as P2O5 because this is the way in which it has been traditionally done (this stems from the fact that old analytical techniques gave the result as P2O5 weight after sample carbonization). Again there is NO P2O5 in commercial fertilizers, there are phosphate species. The same goes for K2O there is NO K2O but K+ this is just the way in which K is reported. Regarding the supplements, you can already do this in HydroBuddy, just set elements you do not want as 0 and you will only need to input salts for those you want. Please make sure you UNDERSTAND what is going on, otherwise you will only fail in using this software. Thanks again for posting,


  • adonis
    November 24, 2011 @ 4:10 pm

    Hi Daniel,

    This program is very good and i tank you very much.
    pleas give me more details about ,seting pH/GH/KH for water quality parameters, and can I calculate amount of phosphoric /nitric acid that is needed to reduce water pH and alter it with HydroBuddy , or i have to calculate amount of acid is needed to discomfit HCo3 and then use HydroBuddy.
    Thank you.

  • December 3, 2011 @ 7:44 pm

    […] http://scienceinhydroponics.com/2011…program-o.html – I think I can help you in the calculations for chemicals. GS_googleAddAdSenseService("ca-pub-9888434945255495"); GS_googleEnableAllServices(); GA_googleAddSlot("ca-pub-9888434945255495", "RIU_skyscraper_header"); GA_googleFetchAds(); GA_googleFillSlot("RIU_skyscraper_header"); Reply With Quote + Reply to Thread […]

  • Nikhil
    December 7, 2011 @ 4:26 pm

    Hi Daniel,

    A great application. Now I actually do not wish to use Excel spreadsheets.

    We are a commercial grower (new) and we are able to verify our results with your application. Helped us locate a number of bugs in our calculations.

    Here, I would like to suggest a few upgrades for your next version:

    1. Please include SOLUBILITY check also. As many time the result show a particular Fertilizer which crosses solubility levels. The bigger issue is that even on identifying such non-soluble levels we can not reduce/limit the amount of a particular Fertilizer (which exceeds solubility level), the only way is to reduce concentration of whole lot.

    2. Practically the Nutrient solutions in STOCK A and Stock B are used for Multiple Crop in a given field. Thus a grower may have to play with ratio of Stock A and B to suit the need of different plants in same field. For example instead of 5ml/Ltr from both tanks, one may use 5ml/ltr from Stock A and may be 8ml/Ltr from Stock B. Wondering if this feature may be added.

    Thus I feel that your application shall assume a lot of further value once these features are added.

    Warm Regards,

  • Bob
    December 16, 2011 @ 6:09 pm

    I am working into using your calculator very nice work. In MAC it does lock up when changing things in the copy formulation window.

    I am working with Amino Acid Chelated Minerals – Ca, Mg, Mn, Zn, Fe and Cu how would I load those into your system?

    I being new to this have not figured out how to actually formulate into a solution but I do get the idea. I do not really get the weight of addition or volume of addition, is that how much you want to put into the total solution?

    Thank you, I will be making a donation next week.


  • Bob
    December 17, 2011 @ 6:11 am

    Hi again, one question about PH buffering. What should we use to buffer our solutions to stabilize our PH. What would be optimal.



  • Dr. R. C. Richardson
    December 22, 2011 @ 10:49 am

    Hello Dan,

    This is a greal little linear progeramming tool. I am a hydroponcs professional and I am wondering if you plant to port this to Android ICS so I can use it on my Transformer Prime. I use the Win version and it works really well. In fact, it works waaaay better than the one Lynette Morgan et al in New Zealand were pimping for years for like $ 300.00 with zero support and a very confusing interface. Confusing for me and I have a Ph.D. in Plant Science and Biochemistry. Please let us know. i for one would pay at least 9.99 for the app as an Android native app.

  • Scott
    December 23, 2011 @ 10:15 pm

    Cannot get Hydrobuddy 1.4 to load on macintosh running Lion 10.7.2. Is there some trick?

    Otherwise, I have used the program on windows while running parallels and it worked fine. Just wondering if I can run it native on a new intel Mac.



  • December 24, 2011 @ 8:55 pm

    i have just installed the latest version of hydrobuddy from the website .
    it downloaded and installed perfectly even worked perfectly untill i closed it

    when i re opened the software it came up with an error message saying “unable to open file ” ow do i rectify this any help apprecited

    • admin
      December 25, 2011 @ 6:09 pm

      Read the comments, the answer is there

  • Jimmy Toucan
    December 24, 2011 @ 10:06 pm

    I’m having issues getting the program to install on my Mac version 10.5.8

    Any help would be greatly appreciated.

  • Volker
    December 29, 2011 @ 7:04 am

    Hello Daniel,
    I found a Problem with the calculation. I tried to find a solution for Lettuce and got this from your program (version 1.4):

    Potassium Nitrate KNO3 35.288 3.5
    Magnesium Sulfate (Heptahydrate) MgSO4.7H2O 45.639 4.6
    Sodium Molybdate (Dihydrate) Na2MoO4.2H2O 0.013 0
    Zinc Sulfate (Dihydrate) ZnSO4.2H2O 0.03 0
    Manganese Sulfate (Monohydrate) MnSO4.H2O 0.154 0
    Iron EDTA Fe(EDTA) 3.077 0.3
    Copper Sulfate (pentahydrate) CuSO4.5H2O 0.039 0
    Boric Acid H3BO3 0.286 0
    Calcium Nitrate (Tetrahydrate) Ca(NO3)2.4H2O 107.346 10.7
    Potassium Monobasic Phosphate KH2PO4 24.198 2.4

    After some days I checked it with the “clean grow” sensor at my university (HTW Dresden, Germany). And the sensor said NO3 856 ppm, all the other Elements were ok. I tested the sensor at other solutions and it works alright. I also checked the calculation with a excelsheet and it always use to much Calcium-Nitrate, I think it use CaNO3 to get the Ca and ignores the NO3, because in the solution were the 182 ppm Ca from the calculation. It also makes this mistake at other formulations, there is always too much NO3. And 856 ppm can make a lot of damage.


    • admin
      December 29, 2011 @ 10:17 am

      Hi Volker,

      Thank you for posting :o) The calculations for Nitrate are CORRECT. I have checked this countless times. For example in your case you have 107.34g of Calcium Nitrate Tetrahydrate which would give you 12.78g of N as nitrate and 18.14g of Ca. If you have 182 ppm of Ca then you would have about 127 ppm of N as nitrate (plus some from the KNO3). Note that you could NEVER have more N as nitrate than Ca in your solution coming from the calcium nitrate because this is simply impossible (there is 16.9% Ca and 11.9% N on this salt). The problem probably stems from the fact that your meter gives you ppm of NO3- and not ppm of N as nitrate (so you get 856 ppm of NO3 when in reality this translates to just 188 ppm of N as nitrate, which is what the program calculates). Please be VERY aware of what your sensors tells you and what the calculations are all about (how could a sensor give you so much N as nitrate when this is simply impossible from the composition of the salts and their amounts?), Hydrobbudy is not a replacement for chemical knowledge. The calculations in HydroBuddy are CORRECT in this case, otherwise thousands of people would have already killed their plants. As I have said this has been checked countless times and I just checked again for your case and confirmed that it works PERFECTLY FINE. In your case – and all cases – the program DOES use N from all sources (check the button on the results page where you can see contributions from each salt). I hope this helps,

      Best Regards,


  • Rob
    December 29, 2011 @ 10:05 pm

    Hello Daniel,

    I am having a difficult time trying to procure phosphoric acid 30% in powder or any other form. my recipe calls for 239.570 grams of H3PO4 30% can you help me find a source as I am at a standstill at this point.

    Thank you for your time in this matter.


  • […] out HydroBuddy if you haven't already seen it http://scienceinhydroponics.com/2011…program-o.html Also, an easier way possibly to run your tests, is to use 1 Liter of water, since you won't waste […]

  • Srikanth
    January 10, 2012 @ 4:51 am

    Hello David,

    I have been using your wonderful calculator for a while now. Thanks for this. I have a question regarding GH & KH.

    My water report states the following:
    Total Hardness as CaCo3 –> 248
    Alkalinity to phenolphthalein as CaCo3 –> 0
    Alkalinity to Methyl Orange as CaCo3 –> 240

    My question is the following correct?
    GH = 248
    KH = 240

    Does adding Ferrous Sulphate make the Calcium in the source water available to the plants?


  • Srikanth
    January 10, 2012 @ 4:52 am

    Sorry I meant Daniel not David.

  • Kurt
    January 18, 2012 @ 5:17 am

    Downloaded the Mac version. Went through the install procedure. The application appeared, but when I went to launch it, it just crashed. Went through the full install again (download, unzip, launch via terminal, walk through installation, crash.)

    Process: hydrobuddy [66204]
    Path: /Users/kurt/Data/horticulture/hydrobuddy.app/hydrobuddy
    Identifier: hydrobuddy
    Version: ??? (???)
    Code Type: X86 (Native)
    Parent Process: launchd [286]

    Date/Time: 2012-01-18 00:10:59.949 -0500
    OS Version: Mac OS X 10.5.8 (9L31a)
    Report Version: 6
    Anonymous UUID: C5DF43B3-EFBA-4B13-821C-E2596C06C4E2

    Exception Type: EXC_BREAKPOINT (SIGTRAP)
    Exception Codes: 0x0000000000000002, 0x0000000000000000
    Crashed Thread: 0

    Dyld Error Message:
    unknown required load command 0x80000022

    • admin
      January 18, 2012 @ 6:46 pm

      Hi Kurt,

      Thank you for your post :o) Sorry but I provide no support for Mac (I don’t have a Mac to test on). I would advice you to download Lazarus and compile/build lazarus on your own machine to ensure you have everything which is needed for proper compatibility. Sorry if I cannot help you anymore!

      Best regards,


      PS: If someone donates me a Mac I could perhaps help :o)

  • […] fertiliser salts do you think exist? Daniel Fernandez who programmed Hydrobuddy certainly does! http://scienceinhydroponics.com/2011…program-o.html I don't need a list of ingredients on the label, I can use that program and I'LL TELL YOU WHAT […]

  • Dan
    January 21, 2012 @ 11:59 am

    I downloaded Hydrobuddy on Windows 7 64bit and it works when opened from the installer but once I close the program and try to reopen it says “cannot open file …hydrobuddy/substances_used.dbf”. Any advice? I have tried to download twice with the same results.

    • admin
      January 21, 2012 @ 12:11 pm


  • Rob
    February 7, 2012 @ 2:07 pm

    Thanks for this nice program!

    I found somthing stanges in the calculations.
    If I do the same calculation in ppm and mmol/L, I get different results, see:


    See the big differences at the Cu result.

    This only happens if water quality parameters are set.

    EC calculation is also different in this situation.



  • joe
    February 22, 2012 @ 5:44 pm

    run it as administrator in win7

  • Tom
    March 6, 2012 @ 6:26 pm

    Hi, so this tool looks really useful, but I’m not a chemist, and I could also use information on what a proper formula SHOULD be, say for outdoor hydro vegatables, and where to buy the raw ingredients. It seems to me that the eBook would be a good complimentary manual to go with the calculator. The calculator is only useful if you already know how to do this.


  • March 7, 2012 @ 7:41 am

    […] […]

  • Steve Sowell
    March 17, 2012 @ 12:56 am

    on the homepage there is mention of a July 06 release date for the next version. I am very hopeful this date is in the year 2012.

    My only recommendation (as most other thoughts/concerns have been corrected in the above comment section) is the adoption of multiple concentrate mixes. I use a 6 part salt scheme and it would be great to be able to tailor solutions based on some set concentrates.
    Instead of A+B dilution ratios I’d like to see A+B+C+D+E+F+G+H (or numbers, it doesn’t have to be letters)…
    For each compound I tried changing the “Concentrate Type” to values of 1 through 6 but this was completely ignored for the dilution ratios on the results page.
    Also, I noticed the PAS extensions in the source archive. Is this in Delphi?

    Excellent utility, thanks for the development!!


    • admin
      March 17, 2012 @ 1:09 pm

      Hi Steve,

      This update date was in 2011, there is currently no target update date (I am too busy right now), I have removed the date to eliminate confusion. The code was developed in Lazarus (FreePascal) NOT Delphi (although very similar in coding structure). Thank you for the suggestion,

      Best regards,


  • Biobit
    March 17, 2012 @ 11:42 pm

    Very interesting and useful your program. I wonder if you have in mind a Spanish version for Latin America and Spain. Congratulations for the great work and thank you for the great help that is especially for non-professionals and beginners like me. Not only do the math easier. It also helps to understand the interactions between all the “ingredients” and variables of hydroponic nutrient solutions. Suggestions that come to my mind: Inclusion in the database some formulations of commercial preparations most commonly used (especially micronutrients).

    Un saludo.

  • alimohammad
    April 7, 2012 @ 8:23 am

    Hi dear Daniel
    thanks for your great softwar
    I am Msc of horticulture science and my thesis was about apple sapling nutrition in hydroponic culture
    i am using your software
    hope you the best

  • Baek
    April 12, 2012 @ 5:59 pm

    Hi Daniel…i am an aspiring hydroponic farmer and stumbled upon your program, however i am unable to use. Whenever i attempt to start the program i get an error message re: opening the dbf files and ultimately the program shuts down. I have tried opening these files with a few progrmas MS access, MS excel and download a dbf viewer program as well. I am no techie but i have attempted a few strategies to the best of my ability but to no avail.

    Please help


    • admin
      April 12, 2012 @ 7:46 pm

      please read the comments, you’ll find the solution there.

  • Michael
    April 19, 2012 @ 1:50 pm

    “Buddy” would not download, always started then “Interrupted” error, though I have a strong WiFi connection. Maybe Google Chrome is a problem and I should try it on Internet Explorer? A little help?

  • Michael
    April 19, 2012 @ 2:01 pm

    Question: Do you know of anyone attempting to go Hydroponic Organic using Worm Tea? I have not found any references to this anywhere on the Net, YouTube, etc. I am able to harvest from 4 to 6 gallons of worm tea (leachate some call it) from my 24 gallon Rubbermaid Tote worm bin on a daily basis and have been using it exclusively in place of regular fertilizer for the past 2 months on my various containers (about 100 plants} on my 6′ x 15′ patio. All I feed the worms is kitchen vegetative scraps, fallen leaves and paper shreds from the office and newspaper. It seems to provide a very complete fertilizer as everything from flowers to tomatoes are growing, flowering and fruiting prolifically.

  • Seph
    April 24, 2012 @ 1:15 am

    Downloaded Mac version. Running Mac 10.7 and when I try to open file to install, it shows up as a Unix executable file with no program to install. How do I install it?

  • beans
    May 26, 2012 @ 10:39 pm

    for mac/osx run program with Terminal to install. google for further instructions.

  • James Megth
    May 28, 2012 @ 2:56 pm

    Hello Mr. Fernandez,

    I would like to inquire about hiring you as a project consultant for two to three small nutrient stock solution projects, and to hire you to modify aspects of your HydroBuddy software. please contact me via. e-mail. I searched for your e-mail address, but it seems this blog is your only public point of contact.

    Thank you, James

    • admin
      June 1, 2012 @ 5:15 am

      Hi James,

      I sent you an email yesterday, let me know if you didn’t get it,

      Best Regards,


  • Dust
    June 1, 2012 @ 4:40 am

    Hello! Good job on the calculator!

    Just a simple question…

    gallon = u.s gallon or imperial gallon?

    Thank you.

    • admin
      June 1, 2012 @ 5:16 am

      gallon = u.s gallon

  • Franco
    July 29, 2012 @ 7:43 pm

    Hi Daniel,

    First of all… Your software is awesome! I’ve been experimenting with it and i love it.

    I have two questions…

    Could you list me the salts/fertilizers that should never be mixed together in concentrate form?

    And also… I have a project where i make keep my nutrients in powder form (bag A and bag B), so they are not concentrated and can be mixed “on the fly” (pre-made for 100gal, 200gal etc…).
    How can i calculate sodium benzoate to add in the bag? (it would just have to last about 7 days mixed).

    Thank you so much!

  • Evgeniy
    August 29, 2012 @ 5:16 pm

    Hello! And you can make the Russian language in the program, I do not know English?

  • Murray
    August 31, 2012 @ 12:05 pm


    Okay, chemicals cost a bomb, so I want to make up hydroponic nutrient solutions based of cheap, mass produced fertiliser formulas, and add whatever might be necessary for completion. My supermarket bought soluble fertiliser has an apparently 27% nitrogen component, comprised of 3% N as nitrate, 2.6% N as ammonium, and 21.4% N as urea. How do I enter the third ingredient into a custom substance formulation?


    • Murray
      September 1, 2012 @ 7:09 am

      Oh, I see. Urea is toxic in hydroponic systems. Okay, we’ll have to find some other source of cheap chemicals, as supermarket fertiliser for plants in soil won’t work too well, it seems. Shame that.


  • leo0108
    September 17, 2012 @ 4:26 pm

    Hi! i am really exciting with your program
    I am studying about Hidroponics and it is very necessary
    but I have a question may you help me?
    “use 10 ml of A and B within every Liter of final solution”
    stand for “5ml A + 5ml B” or ” 10 ml A + 10 ml B”?
    thanks you so much!

    • admin
      September 18, 2012 @ 5:18 am

      10mL A + 10mL B

  • leo0108
    September 18, 2012 @ 3:14 pm

    Hi everyone!
    Can you tell me how to prepare Fe(EDTA)? :)
    I made Fe(EDTA) from Fe2(SO4)3 and Na2EDTA. Is it all right?

  • September 21, 2012 @ 6:42 pm

    Dear Daniel,

    I have installed hydrobuddy on mac with the application terminal. now it is not showing anywhere



  • avant gardener
    September 30, 2012 @ 5:33 am

    1.40 definitely works with osx 10.7.
    it took me awhile to figure out that the .zip file needs to be downloaded from safari (mozilla won’t cut it) and, after it’s unarchived, opened with terminal. voila.

    long as i’m at it, here are a couple other resources i found that are really helpful.

    1. bru’n water is a tool for homebrewerws and craftbrewers to evaluate their water quality in terms of ppm of CaCO3. the spreadsheet runs best in excel, but it also works in google docs and LibreOffice.


    2. AlkCalc is an online pH calculator from the University of New Hampshire. give it a starting pH and a target, and it will tell you how to add of an acid of your choice. it’ll also tell you how much N, P, or S you’ll be adding to the solution as a result.


    Happy Gardening!

  • […] Magnesium, unless you have a formula to add them separately which is again a tedious process. Use hydro-buddy to create your own mixes, PPM values are available in a lot of hydroponic books & is also […]

  • Eric
    May 1, 2013 @ 4:42 pm

    Can’t get ubuntu 11.04 to do anything, even if sudo’ed it says not a command. I am how ever a newb in linux, what am I not seing?

  • Rich P
    May 15, 2013 @ 11:59 pm

    I am looking for a simple clarification…I am using two stock tanks that are 50 gal each… Is the “Stock Solution Volume” in HydroBuddy the sum of stock tanks A and B volumes, or their individual volumes?

    • admin
      May 16, 2013 @ 1:26 pm

      Individual volumes.

  • Dan
    May 26, 2013 @ 10:04 pm

    Hello Sir, have been learning V1.5 for a few weeks now and ran into something that doesn’t make sense.

    I wanted to come up with a formula similar to Botanicare’s Cal-Mag Plus. I determined the ppm #s from the label to be 37-22-59-1.85 (N-Mg-Ca-Fe). When I plug these numbers into ‘Buddy and setup the appropriate substances it comes back with 49-8-49-1.85. Not close on the Mg for a Ca-Mg supplement. However, if I leave out the N input the results come out exactly except for N, which comes out at 73.

    My question is when I put a value into N it limits Ca and when I put no value into N I get the correct Ca?

    Thanks Much!

    • admin
      May 29, 2013 @ 1:25 pm

      Hi Dan,

      Thank you for your post :o) Hydrobuddy is provided as-is (without any formal support). If you want to get an answer to your support question please donate 10 USD to the software using paypal, this supports the software and its development. Thanks again for posting,

      Best Regards,


  • KC
    July 30, 2013 @ 12:28 pm

    Any experience with correcting actuals to calculated values? My first mix was off well over 35% off (short on ppm actuals) on most of the macros and a few of the micros. I have double checked everything, calibrated scales, etc. I can factor all the weights but that far off makes me nervous. Using well known salts from a reputable distributor who is well versed in the CEA industry.

  • Harmen
    August 9, 2013 @ 12:25 pm

    Hi, interesting program :)

    It doesn’t work on a macbook retina :( Going to use it on a windows machine, no problem.

  • Dr S U Patil
    August 15, 2013 @ 6:56 am

    Dear Sir
    Hats off to you for giving a very easy and user friendly programme even alaymans can understand without bothering the properties of the substances. Thanks for uploading V1.5 and for your concern to mankind as these days no body is interested in spreading the knowledge for free. My hearty Congratulations and Thanks Once again…

  • mike
    September 2, 2013 @ 3:37 pm

    Just got a new mac and can not figure out how to get this to install. i get a “no database” message.

    • mike
      September 2, 2013 @ 3:46 pm

      more specifically, “database files not found, please select Hydrobuddy’s installation folder”

      • admin
        September 5, 2013 @ 1:27 pm

        select the folder where the database files are installed.

  • Ed
    September 20, 2013 @ 5:07 pm

    After downloading the executable Linux install file [HydroBuddy-1.50-Linux-x86-Install] I attempted installation whereupon the system said it did not currently have an application available to perform the install and I chose the “search online” function to locate an app. It came back with PyPar2 which I subsequently downloaded and used to open the HydroBuddy Linux install file.

    The install seems to have worked OK with no errors.

    When I try to open the newly created par2 files I get an error message: No applications available to open HydroBuddy-1.50-Linux-x86-Install.par2.
    When I select “Find applications online” another message informs me that:

    Nautilus requires to install software to open files of following type:

    Parchive archive:

    Parchive archive is not supported.

    Kind of stumped at this point.


    • Ed
      September 29, 2013 @ 10:46 pm

      Resolved installation issues.

  • […] Re: Advice on EI dosing I highly recommend Hydro Buddy. It's designed to formulate hydroponic fertilizers but is easily adapted to use in the aquarium. It's got an amazing array of functionality and precision. http://scienceinhydroponics.com/2013…program-o.html […]

  • Jaap
    October 14, 2013 @ 11:01 am

    Some questions, did I miss things?
    1) it seems that calcium nitrate does not include ammonium. in horticultural practice this Ca-nitrate DOES contain NH4. For these cases I have to adjust the formula myself? This is an important cause for mistakes and trouble (NH4 causes pH drop, should be monitored)
    2) it would be nice to be able to calculate ppm to mmole/l resp. µmole/l 0- since I am NL based and we are used to our standards with mmole resp µmole, and this is also what growers from other countries refer to – though they use ppm – ppb.

    I like the program, considering to use it for instruction of international grower/consultants, but not quite sure yet of evt. bottlenecks and practical errors. TEsting.

    • admin
      October 15, 2013 @ 12:37 pm

      1) Calcium nitrate does not contain NH4. If you are using a “calcium nitrate” that contains NH4 then you are NOT using calcium nitrate you are using a calcium ammonium nitrate mixed salt which is incorrectly named as calcium nitrate (see YARA Calcium nitrate on the salt list for an example of such a mixed salt)

      2) I do not understand your request very well. Please give an example.

  • Jaap
    October 14, 2013 @ 11:02 am

    and another minor thing: i have a tendency to use the escape button when entering mistakes etc. – the programm closes and I have to restart. Could it please ask for a confirmation first?

  • Ryan
    October 18, 2013 @ 10:46 pm

    Hi, I love this program, but I am frustrated by one of the limitations.

    Why does the “calculate liquids in mL” box get greyed out when you are calculating by Concentration by Weights?

    This is really annoying, because one of the most common things I want to do, is tell it “add 10mL of this checmical” and just SEE what the results are. but its not possible, you have to use grams and convert manually.

    Seems like a very arbitrary limitation.

  • Joshua Carter
    October 20, 2013 @ 9:28 pm

    seem slike a great application. i keep getting bugs though. great job btw

    • admin
      October 21, 2013 @ 2:02 pm

      please report any bugs so they can be fixed

  • Outre
    October 26, 2013 @ 7:02 am

    Hi Daniel,
    thanks for a great calculator.
    I did notice a discrepancy though and am wondering about the reason for it.
    In the calculator the University of Florida tomato formulations have Ca at 150ppm.
    But if you look at the source paper (http://edis.ifas.ufl.edu/cv216) their recommended concentrations for dry CaNO3 ranges from 35 to 135 depending on the formula.
    So my questions are:
    1. Why doesn’t the calculator’s Ca ppm change between the phases of the plant?
    2. Why is the calculator’s Ca ppm so much higher than the original recommendation.

  • Outre
    October 26, 2013 @ 7:07 am

    Hi Daniel,

    I’m running Hydrobuddy under Ubuntu 13.04 and on startup i always get “no internet connection” message. But the connection is there and it’s good since all of the other programs work fine.
    Is there anything i can do to fix or troubleshoot this problem?

  • Outre
    October 26, 2013 @ 7:09 am

    And one suggestion.
    I think it would be more user friendly to split the comments into several pages and to change the display order from the newest to the oldest.
    Currently in order to see the latest discussion a user must scroll down the entire long page to bottom.

    All the best.

  • dave
    October 26, 2013 @ 9:15 am


    First of all, I love the program, Thanks for the efforts. I have a quick question: There was a custom formula (adjusted to local water) i remember seeing in the past of a Cucumber A&B mix, where iron(along with all the trace elements) and Potassium chloride were in a “B” tank solution (The one in the program has pot-chloride in a “A” tank). “A” tank basically had yara calcium nitrate & magnesium sulphate(mag-sul in both tanks). What would be the reason mag-sul to be in both A&B? Is it ok if pot-chloride goes in either A or B tank? What should i look out for something i shouldn’t put?

    • dave
      November 2, 2013 @ 1:22 pm

      my bad, turns out the formula i saw in tank “A” was yara cal-nitrate & potassium-nitrate

  • David
    November 20, 2013 @ 11:26 pm


    I am interested in contributing to this software but I have been looking at the source code for this program and I can’t seem to work it out, which file holds the formula(s) for the calculation, and what formulas are you using?

  • Ebrahim
    November 26, 2013 @ 2:53 pm

    Hi! This is great. It would be very nice also if you put source code on Github! Github also can provide compiled binaries through release tag. https://github.com/blog/1547-release-your-software Thank you so much! :)

  • robert
    December 13, 2013 @ 9:30 pm


    I am concerned that there are not enough micros in the generic or any of the preloaded databases is this just my lack of knowledge of nutrient solutions or are the databases incomplete? there are a total of 10chemicals in the calculations I receive from this calculator.

    Thank you in advance for any information on this subject.


    • admin
      December 15, 2013 @ 1:00 pm

      Hi Robert,

      Those are all the micros that are needed by the plant in quantities that need to be added. Any other chemicals that plants might need in minute quantities (such as Cobalt) are already present within the other salts as impurities. I hope this helps,

      Best Regards,


  • adithya yagnik
    December 28, 2013 @ 9:16 am


    I have tried downloading the software as i am a mac user with the version of osx 10.9.1

    While installing this software it is showing an error with “unable to install software as it is from unidentified developer”

    Please help!

    Adithya Yagnik

  • […] source: https://customhydronutrients.com/zen…=index&cPath=1 Hydrobuddy nutrient calculator: http://scienceinhydroponics.com/2013…program-o.html Raw nutrient salt source: http://cropking.com/ Reply With […]

  • abolfazl
    January 3, 2014 @ 4:06 pm

    it is not working in windows 8.1

    • admin
      January 5, 2014 @ 7:32 pm

      I don’t officially support Windows 8.1 (as I don’t have it). Only Windows 7 is supported. You can try the linux version on an Ubuntu system as well.

  • January 21, 2014 @ 4:10 pm

    […] need. Honestly, I think I was out of weed when I started arguing. Here's a link to hydrobuddy. http://scienceinhydroponics.com/2013…program-o.html It has a pretty decent tutorial. Originally Posted by TonightYou Hey I'd rather be […]

  • January 21, 2014 @ 9:39 pm

    […] Hydrobuddy nutrient calculator and DIY nutrient tutorials: http://scienceinhydroponics.com/2013…program-o.html Raw nutrient salt source: http://cropking.com/ Posted this in another thread. Could be useful […]

  • Jeff Jones
    January 26, 2014 @ 12:53 am

    Hi Daniel
    I have just come across your program and have downloaded ver 1.50
    I am a very much an amateur and am interested in using a commercial fertilizer as a base and adding to it the necessary ingredients’
    Your program looks very good and thank you for it

    I am having a few problems which I am sure is probably me
    On the Main page I enter
    Tomatoes to termination
    10 litres for VOLUME box
    I tick A+B box
    I tick Input desired Concentration
    I tick commercial Nutrient formulae
    And add
    Ca 0.0001
    S 0.0001
    And press calculate formulae
    Nothing happens so I go to main page and press calculate
    I get a lot of messages to say that various chemicals I selected are incorrect but the program will adjust .ok
    I now get some results
    However if I change to tomatoes or even lettuces the results are exactly the same
    So something doesn’t appear correct

    The other problem I anticipate and I have looked through all the blogs and havn’t found anything.
    Once I have the recommended ingredients from your program, how do I calculate the ingredients I need to add.
    Last query
    There are 2 boxes on the main page to add to data base and one to delete it .How do I access the database to reuse the data?
    Kind regards and thanks in advance Jeff Jones

    • admin
      January 27, 2014 @ 4:15 am

      Hi Jeff,

      Hydrobuddy is provided as-is (without support) if you want some answers to your questions please donate 50 USD to HydroBuddy through the paypal link provided within the program and I’ll reply by email. Thanks for using the software,


  • Gita
    February 3, 2014 @ 7:21 pm

    Hey Daniel!

    Thank you SO MUCH! I have been searching for a way I can make my Hydrophonic nutrient solution and this is just the thing I was looking for. You are amazing! Much love to you from India!


  • David
    February 6, 2014 @ 7:16 pm

    Hi Daniel,

    How does the program decide not to include certain salts in it’s calculations?

    • admin
      February 9, 2014 @ 12:34 pm

      Their coefficients are 0 when the problem matrix is diagonalised. Some salts are eliminated because the optimum mathematical solution simply does not include them.

      • david
        March 6, 2014 @ 8:49 pm

        Thanks for the reply. Can you point me in the right direction for the math on this. I’m trying to figure out how it all works


  • Hydroden
    February 12, 2014 @ 5:41 am

    Hi Daniel,

    Can I check with you when it says Fe Edta 12%, does it means that the purity is 12%?

    Also, when I choose one of the formulas which require Fe to be 4ppm for A+B, how does program calculate and gives the result of 571.429g? Shouldn’t it be simply 400g? I have entered the Fe purity to be 100% btw.

    • admin
      February 22, 2014 @ 1:24 am

      HydroBuddy is provided as-is (without any support), if you want to get support please donate 50 USD via the paypal link provided within the software, then send me an email with your question so that I can reply accordingly. Charging for support helps me maintain HydroBuddy.

  • Robert
    February 13, 2014 @ 9:33 pm

    Hey Daniel,

    I love your hydrobuddy for use with promix, but recently I have been wanting to try some coco cbior and I know that the coco specific nutrients are lower in p and higher in ca. I was wondering if there were some way of producing nutrients suitable for coco from the hydrobuddy app?

    • John
      October 2, 2015 @ 4:30 am

      I’m wondering the same thing.. is there a formula that we can use to transform a standard mix into a coco mix (e.g. decrease K by X%, increase Ca by Y% etc)?

  • Pallab
    March 23, 2014 @ 1:50 pm

    This is a great job. many home gardener love roses chrysenthimum .
    pls wrote aggregate hydroponic nutrient specially for rose & chrysenthimum. thanks for your cotribution in hydroponics gardening world.

  • Manuel
    April 2, 2014 @ 4:57 am

    Hi Daniel,

    I downloaded hydrobuddy v1.5 from this website. I started crunching the numbers by hand and noticed that when I calculated the ammount of Calcium from Calcium Nitrate (as my only source of Calcium)the program gave me a wrong answer !!! By adding 95g of Calcium Nitrate to make a 100 liter solution I should end up with 231.8 ppm and your program tells me 119.59 ppm. Is something wrong with the program or am I mistaken with my calculations ? Please help !!! I want to trust the program but I’m starting to have serious doubts. If you have a more advanced version with fewer bugs I would buy it for sure, this would be an amazing tool !

    • admin
      April 4, 2014 @ 11:35 am

      Hi Manuel,

      Your calculations are wrong. Adding 95g of Calcium nitrate (Ca(NO3)2.4H2O)to 100 liters of solution would give you (40/236.15)*95000mg/100L = 161.21 ppm of Ca and 112.67 ppm of N (from nitrate). This is the exact result given by Hydrobuddy. The program as been extensively debugged regarding calculation accuracy so make sure you check all your calculations and formulas extensively before suspecting a bug within the program. The software is used extensively by both hobby, small commercial and industrial scale growers, so all of these basic calculations have been confirmed to be correctly carried out. If you do find a bug feel free to email it to me at dfernandezp@unal.edu.co (however please confirm with a third party that your calculation results are in fact correct). Thanks for posting,

      Best Regards,


  • salah zoghaib
    April 18, 2014 @ 5:01 pm

    My country Lebanon is not listed in the list of countries to make a donation. Please add Lebanon.

  • Marty
    April 26, 2014 @ 10:30 pm

    You program is awesome. It has helped inspire my son and I. For weeks we’ve been designing a small system for tomatoes. We’ve scrounged/rounded up salts, a pump, PVC, Hydroton, TDS meter, precision scales etc.. and are having a great time learning. Today we mixed our first batch of solution.. and it was twice the PPM that we expected. Can you confirm that we are interpreting the following wrongly. We’ve selected a “stock solution volume” of 2 liters. We’ve also selected “Concentrated A+B Solutions” with a “Concentration Factor” of 100. The way I interpreted this.. we could make a total of 200 liters. When mixing to this dilution our PPM (EC) is twice as high as the software predicts. If we add an equal volume of pure water it of course dilutes the solution to exactly what the program predicts.
    So does 2 liters of A concentrate and 2 liters of B concentrate …. both with a concentration factor of 100… mean we are preparing 200 liters or 400 liters.
    Or quite possibly I have gone astray elsewhere. Thank you for your awesome program.
    Marty in S.C.

  • Marty
    April 26, 2014 @ 11:28 pm

    Please ignore my previous post as it isn’t clear in conveying our confusion with the concentrate mixing instructions in the program.

    With my selection of 2 liter stock solutions.
    (2 liters of A and 2 more liters of B)
    Also I have selected a concentration factor of 100.

    The mixing instructions in the programs states:

    “Values calculated for the preparation of 2 liters of A and 2 liters of B solution. Please use 10mL of A and B within every liter of final solution.”

    I interpret this as meaning I can: Add 10mL of A to 1 liter of water then add 10mL of B to the same water that already contains “A”. Thus a total of 1.02L (1020mL)was prepared.

    Is this the correct dilution of the two concentrates? Or should 10mL of each concentrate be added to it’s own 1 liter…. for a total of 2.02L (2020mL).

    When I prepare 1.02 liters of final solution via first method… my PPM (EC) is twice as high as the program predicts.

    When I prepare 2.02 liters via the second method…. my PPM (EC) is right on target with the programs prediction.

    However I am a total neophyte at this… and this is only my third sample sample solution made and tested with a TDS meter.

    Thank you for your time and hardwork… and I sent ya a little something via PayPal. Not nearly what your worth… but it is what I have available. :)

    • admin
      April 27, 2014 @ 10:23 pm

      Hi Marty,

      Thanks for writing and donating. You’re doing things properly, you should add 10mL of A and 10mL of B for every liter of solution. This means that for 2L (2000mL) of A and B you can prepare 200L (202L final volume). Do not concern yourself with the mismatch between the program’s predicted EC and your EC measurement, the program uses an empirical approximation based on limiting molar conductivities, it might be way off depending on the salts used, their concentrations and final pH. I hope this helps you out :o)

      Best Regards,


  • toni
    May 6, 2014 @ 4:13 pm

    es una pena que no sea en español :=)

  • Mat Roberts
    June 6, 2014 @ 2:12 am

    Hi Daniel. I was trying to use your program on a dry soluble fertilizer that a friend is using on her “run to waste” hydro stack farm. I entered the % values of the nutrients in the “copy commercial nutrient formulation” tab using 25lb. Into 45 gallons, which figured down to 252 gram per gallon. When I hit the calculate key I got amounts in the target concentration ppm fields but no values in the mass or grams. Am I doing this wrong or can you tell me how to get a formula from this % based formula. If we can get gram amounts I feel that we can make it. Any help would be appreciated. Thanks mat.

    • admin
      June 8, 2014 @ 12:12 pm

      Please donate 50 USD using the program’s paypal link to receive support for this issue.

  • Ammonitrate
    June 23, 2014 @ 10:50 pm

    Hello, there is a calculation problem with the following:
    NO3 70, NH4 40, P 30, K 80. Substance selection ammonium nitrate, , potassium nitrate, potassium monobasic phosphate, NO calciumn nitrate. For 100L, the calculator returns 105 ammonium nitrate, 10.8 potassium nitrate, 14 potassium monobasic phosphate. There is way too much ammonium nitrate in the result to be fit with the input ppm. I tried to reinstall Hydrobuddy, but it comes out with the same result.

    • admin
      June 24, 2014 @ 11:49 am

      The purity of the default ammonium nitrate is wrongly set to 30, modify the substance and set it to 100 to obtain the proper result.

  • Nestor
    July 5, 2014 @ 12:59 am

    Dear Mr. Fernandez,
    Firstly, thank you for developing this software I am from a 3rd world country and this really help us a lot. I am just a beginner starting to make my nutrient. Buying premix in our area is very expensive. I have a follow inquiry on the post by Mr. Marty last Apr 26 of which you replied too. My inquiry is you have mentioned that the EC is empirical so we can ignore. So if my target EC is for example 1.5 and the actual measured EC after mixing is 2.4. I can flush out some nutrient amount then add water to lower the EC to 1.5. But with this method, am I lowering also my ppm requirement for each macro/micro element as indicated by hydrobuddy, because at EC 2.4 all are satisfied however flushing out and adding water to get an EC 1.5 will probably lower my ppm value for each of the macros/micros? Please enlighten. Thank you.

    • Nestor
      July 7, 2014 @ 7:28 pm

      Please ignore my previous post. I thought I am just confusing myself. Upon reading between the lines many times I think I now understand why I am getting such a big EC in my final nutrient.
      If my understanding is correct based on what you have replied about A + B implementation.

      On a beaker of 2 Liter water.

      10ml of A, 10ml of B for every liter of solution.

      The final nutrient volume would be 2.02 Liters

      Thus if I understand it correctly, if I have a beaker of 1 Liter water.

      10ml of A, 10ml of B for every liter of solution.

      This will translate to a final nutrient volume of 1.01 Liters.

      I’m sorry if my query is silly. But I just want to calibrate with you Daniel if my understanding is correct. I hope to hear from you soon. Thank you

      • admin
        July 8, 2014 @ 3:06 pm

        For a 1L solution using A+B if you need to add 10mL per liter of each concentrated solution, the final volume would be 1000 mL + 10mL A + 10ml B = 1020mL = 1.02L. Please also remember that HydroBuddy is provided without any support, for a more comprehensive answer to your questions please donate 20 USD through the paypal link within the program.

        • Nestor
          July 8, 2014 @ 11:54 pm

          Hello Daniel,

          I sent you email please check your inbox.


  • melo
    July 11, 2014 @ 7:16 pm

    Hi Daniel,

    I am just having a look into your hydroponics software
    which seems very interesting. However, I could not find the way
    to “substance properties”.How can I see substances characteristics and change the prices?



    • admin
      July 17, 2014 @ 4:57 pm

      Hi Melo,

      Hydrobuddy is provided “as is” with no support. If you wish to get an answer to the question you have posted please donate 10 USD via paypal,

      Best Regards,


  • AJ
    July 12, 2014 @ 7:52 pm

    Love the program!
    I would like to donate as it has helped me so much – what donation is required to get ongoing support?

    a quick question:
    in the Copy Commercial Nutrient Formulation tab:
    what does W/W% and W/V% mean?

    thanks and great work!

    • admin
      July 17, 2014 @ 4:56 pm

      Hi Aj,

      Thanks for writing. Support is given on a per question basis, send me your questions by email to dfernandezp at unal.edu.co and I’ll let you know how much you need to donate. Thanks again for posting,

      Best Regards,


  • rob
    July 21, 2014 @ 11:06 am

    looks good but I am having trouble downloading from the linux link above. I am not sure what kind of file it is, but doesnt seem to want to cooperate with me. Is there another way I can get it so I can give it a try? tks

    • admin
      July 24, 2014 @ 2:25 pm

      Hi Rob,

      The file works correctly for me on Linux Ubuntu and Mint. Try with another browser,

      Best Regards,


      • rjv
        February 21, 2015 @ 6:19 am

        Hi, tks for this great app, but the linux link does not work for me in ubuntu or mint using firefox or chrome, you need to right click – ‘save link as’. If you directly click the download link, you get alot of code characters.

    • end user
      September 18, 2014 @ 11:48 pm

      Just right click on the link and download it locally. You’ll have to do chmod -x HydroBuddy-1.50-Linux-x86-Install in terminal or sudo chmod -x HydroBuddy-1.50-Linux-x86-Install to make the file executable. The in terminal type in ./chmod -x HydroBuddy-1.50-Linux-x86-Install

      This will install it. After that doble click on the hydrobuddy icon in the insall folder.

  • Pete
    July 29, 2014 @ 11:12 am

    Hi Daniel,

    I was unable to install this program on Linux, with it failing with most strange errors, like ‘file not found’ even when it was clearly there. Some investigating seems to suggest the problem is I am running a 64 bit version of Ubuntu (the latest). I have tried various fixes suggested on the web for running 32 bit programs on 64 bit Ubuntu like installing extra libraries but none have worked. You might be too busy to change this but I thought I would let you know. If you have any advise that would allow it to run it would be appreciated, otherwise I might install it on an old windows box I have.

    Best regards, Pete

  • Pete
    July 29, 2014 @ 11:58 am

    Hi Daniel,

    I solved the above issue and thought I should post the solution for other users.

    The problem is indeed the fact that the program is 32 bit and I was trying to run it on a 64 bit system (which most modern installations of Ubuntu will be). The solution is to install a load of libraries. I am not sure which of the following are needed, most of them seem to be, but I am sure there are a couple here that are not required, but not harmful. I found the missing libraries by typing ‘ldd HydroBuddy-1.50-Linux-x86-Install’, which provided a list of missing libraries (many lines like ‘libX11.so.6 => not found’ etc).

    Anyway the fix is to type the following at the command line:

    sudo dpkg –add-architecture i386
    sudo apt-get update
    sudo apt-get -y install lib32z1 lib32bz2-1.0 lib32ncurses5 libgtk2.0-0
    sudo apt-get -y install libc6:i386 libncurses5:i386 libstdc++6:i386
    sudo apt-get -y install libx11-6:i386 libgdk-pixbuf2.0-0:i386
    sudo apt-get -y install libglib2.0-0:i386 libcairo2:i386 libatk1.0-0:i386
    sudo apt-get -y install libpango-1.0-0:i386 libgtk2.0-0:i386

    You can copy and paste it. This fixes the ‘file not found’ error on the 64 bit edition of Ubuntu when you try to run the Hydrobuddy program. You might have to type your password if it asks you.

    Thanks Daniel for the program, I will have a play round with it now.

    Best regards, Pete

    • Pete
      August 4, 2014 @ 12:14 pm

      Please note with regard to the above, its meant to be

      sudo dpkg – – add-architecture i386

      with no spaces between the minus minus add, rather than

      sudo dpkg –add-architecture i386

      as it comes out on this page.

    • Wouter
      October 28, 2014 @ 5:49 am

      I got the same problem you had, installing it on Linux Mint 17.

      After adding the i386 architecture, the following two lines were enough to get it to run:
      sudo apt-get -y install libx11-6:i386 libgdk-pixbuf2.0-0:i386
      sudo apt-get -y install libpango-1.0-0:i386 libgtk2.0-0:i386

      However even after installing the rest, one issue remains:
      “Automatic update failed: No internet connection” it says when starting up.

  • Matt
    July 29, 2014 @ 6:52 pm


    I’m attempting to install the windows v1.5 of your program on my computer but keep getting this error

    – Unable to create file “C:\Program Files (x86)\HydroBuddy/hb_install.zip” Press OK to ignore and risk data corruption. Press Cancel to kill the program –

    Not sure if it is important but there is a forward slash / in the directory before hb_install.zip while the others are all back slashes \. I’m not too computer savy but that stood out to me. The 1.4 version installed fine but kept crashing on loading due to a substance_used.dbf error. Hope to get it working.


    • admin
      July 29, 2014 @ 9:47 pm

      Run installation program as administrator. Right click “Run as administrator”

      • Matt
        July 30, 2014 @ 7:09 pm

        Ran v1.5 as administrator and it seemed to install fine,but when attempting to run the program it brings up the Unable to open substances_used.dbf error then crashes. I checked and the file is present in the directory..

        • admin
          July 30, 2014 @ 8:07 pm

          Also run Hydrobuddy as administrator, right click “Run as administrator”

          • Matt
            July 31, 2014 @ 10:02 pm

            Thanks, got it to work. Feel kinda dumb now :)I did find a tiny little bug. On the results page the Mass column in the top table always shows grams as the unit in the column header regardless of whether you select grams or ounces on the main page. The calculations appear to be carried out correctly though.

  • Pete
    July 30, 2014 @ 3:06 pm

    Hi again Daniel,

    I’ve been playing round with some formulas using your HydroBuddy program and I must say its very helpful to understanding fertilizer mixes, as well as calculating constituents.

    One thing I am wondering though is does the program take account of the individual solubility of all compounds generated by mixing the constituents? IE I tried a mix using iron nitrate with ammonium monobasic phosphate, selecting ‘direct addition’, and the program allows me to do this. But then I realized I am not sure if the above 2 chemicals are compatible even in this low concentration (from my limited understanding of chemistry, I looked up the Ksp of iron phosphate at about 1*10^-29 which seems much lower than would be achieved with Fe = 1ppm and P=30ppm, which I calculate as 5.7*10^-9 in the unlikely event that I got that right!).

    If the program does not ‘account’ for this, what do you recommend to users to make sure they don’t come up against this kind of problem. Is it necessary to calculate and check the Ksp for each possible compound created by a particular mix? Or just follow a few rules like never use unchelated iron with phosphorus?

    Thanks and best regards,

    • admin
      July 30, 2014 @ 8:07 pm

      Hi Pete,

      Thanks for writing. Hydrobuddy is provided “as is”, without any support. If you want an answer to your question please donate 20 USD via the paypal link within the program,

      Best Regards,


      • Pete
        August 4, 2014 @ 11:07 am

        Hi Daniel,

        Thanks for the info, I will probably need this support once I start using the program properly next year. This year I have left it too late to start growing anything unfortunately, so I will wait until I need the help.

        Kind regards, Pete

  • SPAK
    August 25, 2014 @ 9:09 am

    First of all I would thank u for your awesome program and great work that helped me a lot.

    Btw there is a bug, when u calculate and check the “calculate liq in ml”, then after that u can’t change any thing in Results tab because of the error happen in strings.

  • Son Vo
    September 18, 2014 @ 4:30 am

    Wow, I like it. I use software in invitro stock.

  • Suraj
    October 5, 2014 @ 4:33 pm

    This is an awesome tool. A true life saver for humans and plants alike :)


  • Rohan
    October 17, 2014 @ 5:04 pm

    Hi Daniel, awesome tool. This tool actually makes the life so much easy who want to do commercial hydrophonics. If possible please give me your email-id. I can give suggestions for improvements, if any.

    • Ike
      December 12, 2014 @ 4:06 pm

      I was wonder if you use this for comm grows I take it that it also can be used for smaller grows? Do u mix your nutes from dry or do you use liquid nutes like advanced nutrients, general hydroponics etc?

  • Pavel
    October 26, 2014 @ 8:09 pm

    Dear Daniel,

    Thank you for producing such a great app for all us hobbiest out there, spreading knowledge.

    I need your expertise with few things and was hoping you could offer me support and advice.

    I would be more the happy to contribute towards your efforts.

    Please email me if possible

    Many thanks

    Kind regards Pavel

  • Commander Rao
    November 27, 2014 @ 12:45 pm

    Hi Daniel,
    I am a Dairy Farmer from Bangalore, India and grow Fodder in Hydroponic Trays.
    Would like to talk and seek guidance from any of your Indian users familiar with Hydrobuddy 1.5.
    I can be contacted at: cdrdrm@gmail.com or 09535356345 (Bangalore,India)
    Commander Rao (retd)

  • Juan Diego Martinez
    January 15, 2015 @ 9:22 pm

    Apreciado Daniel,

    Me gustaría establecer contacto contigo para que me asesores en la fertlización de mi cultivo de aguacates en Sasaima (a 90 min de Bogota). Estoy en proceso de instalar un Fertiriego por goteo… y quiero preparar mis propios fertilizantes a partir de lo que muestran mis resultados foliares (tres año) y mis estudios de suelos (uno al año). Tengo 4.500 arboles sembrados en 5.5 hectareas. El 50% ya está en producción).

    Mi cel es el 313 252 6262

    Gracias, Juan Diego

  • tobh
    February 16, 2015 @ 5:29 pm

    Just an idea, you need to compress the executable for Linux. Either your server is trying to interpret the executable as a code/text file or my browser is trying to view it as such and we all know what happens when you view the “text” of an executable. ASCII artifacts spewed all over the screen and no successful download. A right-click, Save Link As… works to achieve the download, though beginning *nix users may not realize this. Just offering some input. Looks like a good program though! Perhaps some documentation notifying of required dependencies would be helpful, as I had to install a couple gtk libs to get it to function. Thanks for your work on this!

  • Sofia
    April 21, 2015 @ 2:23 pm

    great job

  • zuilfqar
    April 26, 2015 @ 1:47 am

    Hello Daniel,
    I did denoted $ 10.00 through paypal for your support

    I like to prepare 20:20:20 along with micronutrients for my Hydroponic system

    what and how much compound/elemenmts I should use in your software to get 20-20-20 blend

    and how i should use your software.


    zuilfqar shah

  • William
    May 15, 2015 @ 1:58 pm

    Will not install on windows 8, says it cannot create install.zip

    • admin
      May 15, 2015 @ 11:58 pm

      Run as administrator.

  • Amr
    May 15, 2015 @ 10:20 pm


    There is a pretty basic mistake here in this software. When calculating NO3, it gives me the final ppm of N, not NO3. For example, 1g of CaNO3 gives a Ca result of 169.7ppm and an NO3 result of 118.6ppm. This is not correct as the molecular weight of NO3 is higher than that of Ca, so it is impossible to have more Ca ppm than NO3 if CaNO3 is added alone. The correct ppm for NO3 should be around 600 in this case, so it’s quite far off from what should be.

    I would appreciate if you can fix this so I can get back to using your excellent software!

    • admin
      May 15, 2015 @ 11:56 pm

      The software does not give you the ppm of NO3- as NO3- it gives you the ppm of NO3- as N. When you see formulations (NPK or otherwise) nitrogen is reported commonly as ppm of N in NO3- or NH4+, not of NO3- as a full ion. There is no mistake in the software, this is simply the way in which nitrogen concentrations are commonly reported in commercial settings.

  • Jarred
    May 19, 2015 @ 3:54 am

    Are you still working on this program?

    I don’t see where it shows which salts to put in A and which to put in B.

    I’m trying to find formulas that fit with the scientific paper “Nutrient Management in Recirculating Hydroponic Culture” have you looked into this?


  • […] Como he mencionado antes, HydroBuddy es gratuito y está disponible para Windows, Mac y Linux en su página. […]

  • swede
    May 29, 2015 @ 1:22 pm

    The linux version of the download just comes up as garbage
    what language is it in?
    any chance of getting a package or something compilable
    kubuntu doesnt seem to know what to do with it

    do i need a specific package installed to make use of the code.
    will be a happy donator if it works.


    • Octavus
      February 16, 2016 @ 12:33 am

      I’m with swede on this.

      Really interested in this program Dr. but I need it in Linux as I’m dead set against Micro$oft.

      In the mean time I’m going to have a gander at the source and compile myself. Well try anyway.

      • admin
        February 20, 2016 @ 2:52 pm

        Linux binaries are available for download (just tested they work perfectly well on latest Mint and Ubuntu).

  • Joe
    July 3, 2015 @ 2:24 am

    Thank you for your amazing work and knowledge!

    I have a few questions. This year I have started growing Hydroponic Tomatoes. Most of my knowledge has been obtained from the many YouTube videos I have watched over the past year. The tomatoes are doing well but the nutrients I am using are not giving me the control I need. I plan on commercializing in the future. Your program has helped in so many ways. I have yet to purchase the compounds I would like seperately (I have a link to an old post you made). The main reason for this is because the tomatoes are doing really well and I have spent the money on a 25lb bag. I am using Masterblend 4-18-38 w/ Calcium Nitrate and Magnesium Sulfate. I am having a difficult time obtaining the correct breakdown of the nutrients in Masterblend to add to the program. Here is the information it gives:
    Total Nitrogen (N)…………….. 4%
    3.5% Nitrate Nitrogen
    0.5% Ammoniacal Nitrogen
    Available Phosphate (P2O5)……… 18%
    Soluble Potash (K2O)…………… 38%
    Magnesium (Mg) (Total)…………. 0.50%
    Boron (B)…………………….. 0.10%
    Copper (Cu)…………………… 0.10%
    0.10% Chelated Copper (Cu)
    Iron (Fe)…………………….. 0.40%
    0.40% Chelated Iron (Fe)
    Manganese (Mn)………………… 0.20%
    0.20% Chelated Manganese (Mn)
    Molybdenum (Mo)……………….. 0.01%
    Zinc (Zn)…………………….. 0.10%

    Plant nutrients derived from: Potassium phosphate, potassium nitrate, ammonium phosphate, potassium chloride, magnesium sulfate, boric acid, copper EDTA, copper sulfate, iron DTPA, manganese EDTA, sodium molybdate, zinc EDTA.

    11.34KG (amount in bag) = 25 lbs

    Potential Basicity: 209 lbs Calcium Carbonate Equivalent Per Ton.

    Maximum Solubility 2.3 lbs Per gallon.

    My questions are the following: (I have sent 20$ on paypal and will send another 20$ or more as soon as I get this figured out)

    Do I need to breakdown Nitrogen into NO3 (just as we would breakdown P2O5 and K2O)?

    Where do I get the formula for Ammoniacal Nitrogen?

    Just to confirm I am doing the K2O and P2O5 correctly.
    K2O = .38 x 11.34kg = 4.31kg x 0.83 = 3.58kg
    3.58kg/11.34kg = 31.57% K

    The above nutrients show sulfate as being added but no percentage for S?

    I have no idea how to breakdown chelated items or what that even means.

    At this point I have been able to breakdown all of the nutrients from the specific compound using molecular weight and atomic weight to find the conversion factors. That is simple. I just want to know how to break this down to see what I am adding.

    • admin
      July 6, 2015 @ 1:48 am

      1. No need to modify N. The % of N as nitrate is already given as N. Simply enter this % value in the program (3.5%)
      2. The % value for nitrogen from ammonium is given (0.5%) simply enter this percentage in the program for ammonium derived nitrogen(NH4+)
      3. You do not need to convert them. The program allows you to add K as K2O and P as P2O5 (change the type of K and P using the dropdown menus next to these nutrients when you add a substance).
      4. Fertilizer companies are not required to report the % of S. You can simply leave it as a degree of freedom, plants tolerate a wide range of S.
      5. Don’t worry about the “chelated” part. Simply add the % that is on the label for each metal (Cu=0.1%, etc).
      6. These elements (except K and P) are already reported in the % values that you enter into the program (% composition of the element) you don’t need to carry out any conversions (even for K and P you don’t need to as you can change the input in Hydrobuddy to K2O or P2O5).

      PS: In the future please inquiry before making a donation if you are making it for support as I might not have the time to answer promptly ;o)

  • Tina
    July 6, 2015 @ 2:12 pm

    Thank you for your VERY helpful APP

    We have organic plant fluid (liquid/thick/brownish)

    Nitrogen 53 g/kg
    Phosphorous 7 g/kg
    Potassium 17 g/kg
    Calcium 0.5 g/kg
    Magnesium 1.5 g/kg
    Manganese 2 mg/kg
    Iron 170 mg/kg
    Copper 1 mg/kg
    Zinc 37 mg/kg
    Boron 17 mg/kg

    How does this measure up in strength with other chemicals

    In comparison with Potassium Nitrate it looks very weak

    Can you PLEASE give an insight

    Try to add this to Hydrobuddy

  • Tina
    July 8, 2015 @ 4:32 pm

    Great Work
    I am new to Hydroponics
    Why are some Elements not in the formulas

    Not used by Plants ?
    Maybe quantities too small ?

    Thank you

  • Majed
    July 20, 2015 @ 8:18 pm

    Can you please explain why you are using molar weight for the Ca (NO3)2 as 236g/mol?
    The reason am asking is that some sites use 164 and other uses 236.

    • admin
      July 21, 2015 @ 1:25 pm

      There are different types of calcium nitrate:

      calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) = 236g/mol
      calcium nitrate (Ca(NO3)2) = 164 g/mol

      The tetrahydrate is the most commonly found form of pure calcium nitrate. Most commonly you can also find the mixed ammonium/calcium nitrate (what Yara sells as calcium nitrate), which has a different molar mass.

  • Majed
    July 21, 2015 @ 3:46 pm

    Thank you so much for the clarification. I have gained some valuable information about hydroponic nutrients solution connotation from the above discussions.

  • Tom
    July 25, 2015 @ 12:36 pm

    WoW great work on this app

    We try to determine how to add human pee to HB
    5% Chemicals 95% water


    If I am correct
    Must add as above BUT Purity at 5%
    Because 5% of pee is Chemicals

    Thanksin advance

  • August 31, 2015 @ 9:37 am

    Hi there, I bought you program (Hydrobuddy) on Ebay from a UK seller. I am in Australia. I got the mac version of the program, I have a Mac OS x 10.10.5 to run the program, however I am not able to run the program, I download a app to read dbf files but still not working. Dear Daniel, could you please help me with this issue, I really exited about you program, I already bought it and I will like to made a donation also, please let me know, thanks a lot, and I can’t wait to be able to run the program.


    Octavio G

    • admin
      September 19, 2015 @ 1:39 pm

      The program is available completely free of charge. I would advice you to initiate a paypal claim against the seller of this program on ebay. He is certainly violating the program’s GPL license by trying to sell it.

  • Kevin
    September 8, 2015 @ 9:51 pm

    Hi Daniel,
    I have a question regarding hydroponic formulas that perhaps you would be so kind enough to answer. If I am trying to do my calculations for a formula where I want 200ppm Ca and N.
    For Calcium I will use Ca(NO3)2 with 90% purity. I want to make a 200x concentration. I have 30 ppm Ca in my raw water.Not
    Correcting for impurities I will get 696mg/l corrected for impurities it is 773mg/l
    When I want to figure out how much N the Ca(NO3)2 why do I need to use the 696 mg/l instead of the 773 mg/l to calculate the contribution to my formulas N?
    Thanks for your help.

  • Jennifer Martin
    October 4, 2015 @ 8:31 am

    Hi there, I’m also having trouble getting the program to install on Mac OSX. I’m on 10.7, and none of the downloaded files initiate a successful installation. I tried emailing in twice to ask for help, but no one answered.

    • admin
      October 4, 2015 @ 2:24 pm

      The program is provided “as-is” (meaning without support). The source code is also available if the executables don’t work for you and you want to compile for your own platform.

    • greengenes
      October 20, 2015 @ 9:27 pm

      Did you ever get it figured out. For me it is saying there is no database, then closing out. I am running OSX 10.10.
      It was working sort of last night…now won’t even stay open.

  • Chris
    October 12, 2015 @ 6:54 pm

    Good day!

    I am working for my project and having hard time finding the proper mix for 1 solution. I am willing to compensate your assistance for my project (proper chemical mixture of 1 solution only using your good software). Please send me a message via email Thanks very much! Hoping for your positive response!


  • Tim
    November 29, 2015 @ 10:53 pm

    Is it possible someone could add a 64-bit Linux download? Or, provide instructions about how to compile the source?


  • Jordan
    December 8, 2015 @ 8:28 am

    Daniel, great job on HydroBuddy. Compared to a paid service like Smart-Fertilizer, it does pretty much all the same stuff. A few questions:

    1. Do you have plans to add Urea, N-NH2?
    2. Do you have plans to allow the solver to work off a total N target and apply NO3 or NH4 as it needs?
    3. Any plans to work on a solution pH calculator? Working a pH target into the solver as well.

    4. If you aren’t planning it yourself, would you mind helping me get up to speed with things in Lazarus? More of a “This is where this is and this is what it does” sort of thing so I can make these changes myself to the source code. The code is not commented all that well, so it’s a bit difficult to navigate and learn it at the same time. Additionally, I’d certainly like to learn more about the solver and how it works.

    Feel free to email me.

  • Julia Eileen R. Chiu
    December 26, 2015 @ 12:32 pm

    Good day Mr. Fernandez, i have been growing hydroponically and have really appraciated the app! have even donated $20 and hoping some assistance with the — Generic for berries (growing edge) default nutrient mixture.

    Chemicals used:
    Potassium Nitrate
    Calcium Nitrate
    Phosphoric Acid
    Magnesium Sulfate
    Iron Edta
    And other micronutrients listed in the hydrobuddy

    These chemicals were weighed perfectly in an analytical weiging scale assisted by a chemical student

    Upon my mixture it resulted to a PH:6.4 ; PPM: 500 – 750; Using a Distilled water

    My problem is after testing it to plants i cant see anyroots development..

    Have tried the default lettuce formula still no root growth from lettuce.

    Any assistance as to what i can do next? Do i need to have my mixed chemicals analyze in the laboratory and send it to you for you to check? hoping really for a great advice thanks!

  • beau
    December 29, 2015 @ 7:36 am

    Wow The first to Congratulate the new Doctor here!

    • admin
      December 31, 2015 @ 1:02 am

      Thanks a lot :o)

  • lettuce
    January 10, 2016 @ 12:20 am

    Hello, program doesnt start on windows 8.1. First pop-up window says it is up-to date and after confirming it shows running program in program bar, but no window shows up.

  • Sushil Wankar
    March 17, 2016 @ 5:20 pm

    Hi, i have calcium nitrate, NPK: 19-19-19, NPK 0-52-43, NPK 0-0-50, magnesium sulphate, and EDTA chelated Micronutrients mix as Fe 2.50%, Mn 1.0%, Zn 3.0%, Cu 1.0%, Mo 0.10%, Boron 0.50%. Can somebody help me that how many grams(each of the chemical) shoud i use to make hydroponic solution for 5 gallons of water. I am very weak with the mathematics so I am confuse how many grams should i use for each of the nutrients in grams per 20 litter. Please help me to make hydroponic solution with available nutrients. Please ..please.. help me.

  • AZS
    March 19, 2016 @ 2:58 pm

    Congratulations Doctor. Your program has evolved nicely over the years, thank you!

  • Benedict Espiritu
    April 9, 2016 @ 10:25 am

    Hello Every one!
    Actually the formulation of this was base on its Recommendation Rate per plants. Meaning, if you going to plant lettuce to have the maximum group you must apply 240kg of N, 60kg of P2o5, 60 k20 of fertilizer / hectare. So if the planting distance is .16X.16m, and in one hectare we have 10000sqm = .0256sqm planting distance… so 10000/0.0256 = 390,625 is the total population of lettuce per hectare… so 240 = 240000grams , then 240,000 grams / 390625 = 061g per plants of lettuce. do it same with P2O5, and K2O … email me benedict_lajada@yahoo.com.ph for inquiry …… thanks

  • Sue Piatt
    April 16, 2016 @ 4:23 am

    Valuable suggestions – I loved the details ! Does anyone know where my business would be able to get ahold of a blank MD MS-100 version to fill in ?

  • Mojtaba
    May 13, 2016 @ 7:00 am

    Hi Professor
    Thanx for Hydrobubby.
    I have a Request.
    Can you add Cobalt element in HydroBuddy? I think is Necessary.
    thnax Professor.

  • samuel dabney ware
    May 15, 2016 @ 9:46 pm

    Daniel I would like to visit with you on the phone on these formulas for a hyrofarm im involved with. what is your number thanks Sam

  • Tina
    June 1, 2016 @ 7:58 am

    We have a problem obtaining the chemical breakdown of fertilizers

    Does anybody know where to get it from online

    Thx in advance

  • Zequez
    June 2, 2016 @ 7:27 am

    For anyone trying to run or compile on Mac: just use Wine with the Windows version, it works fine.

  • Tina
    June 3, 2016 @ 5:58 am

    Where can we get hydrobuddy updates which are installed when starting hydrobuddy

    Needs it for offline install/update

    thx in advance

  • Fred
    June 3, 2016 @ 7:01 pm

    Thx in advance

    Needs details for Spinach pretty please

  • June 11, 2016 @ 6:01 am

    thank you so much, iam starting use this great-powerful program today :D

  • luis guerrero
    June 14, 2016 @ 6:31 am

    hola seria posible una versión en español

  • Matthew
    June 15, 2016 @ 10:27 am


    please i am currently using an hydroponic solution to run an Experiment for my master thesis,the aim of my experiment is to check the possibilities of salvinia natans in the removal of contaminants from a waste water and also to Evaluate the growth response of these plants and this my contaminant of concerns are nitrogen and phosphorus.
    My main issue of concern is that the sample with phosphorus is having a low conductivity of 150 while that of Nitrogen is having 750 mean while all has the same basal medium constituent. and also the solution with phosphorus has a Ph that is decreasing constantly from a Ph of 6.5 to 5.7, 5.4, 4.3 etc. please i will like to know if there is another way to achieve a better result

  • Bharat
    July 22, 2016 @ 6:57 am

    Looking forward for practical training in Hydroponics in Pune India.
    I want to seriously work on this for next 20 years or so.
    Bharat Ketkar

  • Dinesh Bhojwani
    August 3, 2016 @ 7:54 am

    Wow Daniel …. Dr. Fernandez :-) Congratulations!

    I’m amazed with the software you have developed!
    I’m a Novice in hydroponics and have just started in this journey.

    Your software is helping me understand a lot of things.

    Warm Regards

  • Chuck
    August 11, 2016 @ 11:41 pm

    2 questions/comments.

    1. When using the “Calculate liquids in mL” option, any changes made to the Mass in the Results tab crashes with errors such as “39.911 mL” is an invalid float. Even if you are adjusting something listed in grams it still crashes if something else is listed in mL.

    2. Why does having extra substances that aren’t used in the final mix make the results inaccurate? I would like to do certain things such as being able to tweak the final Calcium Nitrate vs other calcium sources I might prefer but if I leave an extra calcium in there, the nitrogen gets calculated way higher than it should.

    • Chuck
      August 11, 2016 @ 11:43 pm

      P.S. I’m aware you don’t offer support, and I don’t necessarily need it I’m just giving my opinion as a user that these 2 things are quite annoying and would consider fixing if you ever continue your work. TY for your great software and for providing it for us struggling poor farmers :)

  • Simon
    August 23, 2016 @ 5:05 pm

    Hi Doc.
    Am very grateful for this great piece of app. I have had some interest in starting hydroponic farming and feeding the plants was my biggest riddle.
    Thou sourcing the chemical here in Kenya will pause a challenge, I bet your contribution has come in handy. Any future developments are eagerly waited to enrich our pockets and our minds. Kudos

  • Jon
    September 7, 2016 @ 10:01 pm

    I’m amazed at how many of you individuals ask for more and more despite the being FREEWARE. Like seriously, some of you all are so greedy and ungrateful… Thank you Dr. Fernandez for being the type of individual the world needs. It needs many more like you.

  • Edgar
    September 30, 2016 @ 6:30 pm

    Does the installer take include paths? If so, how?

    edgar@evermore:/home/hermit/Downloads# ./HydroBuddy-1.50-Linux-x86-Install
    ./HydroBuddy-1.50-Linux-x86-Install: error while loading shared libraries: libgdk_pixbuf-2.0.so.0: cannot open shared object file: No such file or directory

    edgar@evermore:/home/hermit/Downloads# locate libgdk_pixbuf-2.0.so.0

  • October 5, 2016 @ 12:45 am

    Dear Daniel,

    Thank you SO much for your amazing calculator. I would like to pay you for a consultation, as I live in Argentina and getting a hold of Iron EDTA or EDDHA is practically impossible. So I would like to be able to make my own. I have a formula that is working with spectacular results, but am currently unable to get more of EDDHA. I have a source for dipotassium EDTA & Iron oxide powder. Can you please help me setup my HydroBuddy formula to work with ?

  • Harish Chandra
    October 25, 2016 @ 7:06 pm

    Just downloaded your hydrobuddy program. The download material has numerous files; could you please tell me which specific file opens up the program that can be used to calculate the nutrient components, quantities, etc. to arrive at a desired mix. Thanks

  • November 7, 2016 @ 6:49 pm

    Hi. I cant get Zinc Sulfate (Dihydrate). Can i replace it with something else?

  • Pramod
    November 28, 2016 @ 1:53 am

    Hi Daniel,

    I’m trying to download HydroBuddy but its not working. Can you please help?

  • Andrew
    November 30, 2016 @ 8:13 pm

    I’ve setup Lazarus 1.6.2 and FPC 3.0 on macOS Sierra and when I try to compile, I am getting a lot of errors:

    Compile package LCL 1.6.2: Exit code 256, Errors: 12, Warnings: 1
    carbonproc.pp(513,13) Error: Identifier not found “ATSUFindFontFromName”
    carbonproc.pp(536,14) Error: Identifier not found “ATSUFindFontName”
    carbonproc.pp(543,14) Error: Identifier not found “ATSUFindFontName”
    carbonproc.pp(564,11) Error: Identifier not found “FMGetFontFamilyFromName”
    carbonproc.pp(671,5) Error: Identifier not found “HIViewChangeFeatures”
    carbonproc.pp(674,11) Error: Identifier not found “HIViewSetVisible”
    carbonproc.pp(675,11) Error: Identifier not found “HIViewSetFrame”
    carbonproc.pp(698,3) Error: Identifier not found “GetControlBounds”
    carbonproc.pp(708,3) Error: Identifier not found “SetControlData”
    carbonproc.pp(733,36) Error: Identifier not found “GetControlEventTarget”
    carbonproc.pp(1369,12) Error: Identifier not found “GetThemeFont”
    carbonproc.pp(1369,43) Error: Identifier not found “GetApplicationScript”
    carbonproc.pp(1371,28) Warning: Local variable “sz” does not seem to be initialized

    As other comments have stated, a quick tutorial on how to compile would be great. I assume I’m missing something very simple. Thanks in advanced, I can’t wait to get started using HydroBuddy!

  • Neil Jackson
    December 3, 2016 @ 5:43 am

    Hi Ive just downloaded the windows version and its not installing on Windows 10
    its unable to create file C:\hydrobuddy/hb_install.zip

    • admin
      December 22, 2016 @ 5:24 pm

      Run the installer as administrator.

  • adjie
    December 21, 2016 @ 2:24 am

    Hi Dr. Fernandez,

    could you please give step by step how to compile the source code in OSX since I don’t have windows and linux platform only mac.


    • admin
      December 22, 2016 @ 5:23 pm

      Hi Adjie,

      Thanks for writing. I do not have a Mac so I cannot provide you with a step-by-step guide on how to compile using a Mac since software installation is bound to be very different. You’ll need to search online how to install Lazarus and then attempt to compile the source code there yourself. Also bear in mind that HydroBuddy is provided without support (for support please send a support request to dfernandezp@unal.edu.co and I’ll reply with a quote depending on your support need). Thanks again for writing,

      Best Regards,


    • August 31, 2017 @ 2:33 am

      Dear Adjie, did you manage to get HydroBuddy compiled under OSX? I tried, but ran into errors I was not able to solve completely. I installed Lazarus via homebrew (brew cask install lazarus). To compile HydroBuddy you have to set the widget toolkit from Cocoa (native) to qt. After that the compile runs trough, but at the very end I get an error message saying that there was an error while linking. I have no idea on what is going wrong and how to solve this. Any hints and pointers appreciated.

  • Brandon Goyette
    January 9, 2017 @ 1:52 pm

    Great job! Whatever happened to the databse aspect?

  • Sushil
    January 10, 2017 @ 5:51 am

    Can i use manganese chloride instead of manganese sulphate?

  • Dany
    January 24, 2017 @ 4:05 pm

    Bonjour et felicitation pour votre travail je ne parvien pas a l instaler je suit sur windows 7 que faire merci d avance

  • Dave - GROWER
    February 10, 2017 @ 1:25 pm

    Is anyone out there well versed in using the Hydrobuddy tool?

    I am looking for some education, and am willing to pay for your time

  • piero
    March 13, 2017 @ 2:22 pm

    Thank you Sir for the valuable tool.
    But there’s a feature totally unclear to me: the gross error.
    I see that the difference from the target ppm and the result is zero for a specific element while the gross error is often not zero.
    Othewise on a specific composition requiring NO ammonia, the gross error is 0 while the computed ppm is 30.
    Regards. Piero Zanotto

  • April 11, 2017 @ 12:49 pm

    Dear Daniel,
    Is there version of hydrobuddy for win-32 bits?
    If so, could you send me the 32-bits version by email?

    • admin
      April 11, 2017 @ 1:31 pm

      Hi Rodrigo,

      Thanks for writing. There are no 32-bit precompiled binaries. If you want to use hydrobuddy on windows 32-bit you should download the source and compile it using Lazarus. I hope this helps,

      Best Regards,


  • June 21, 2017 @ 7:21 pm

    Hi Daniel

    Thank you for your great software , i use your software to made fertilizer formulas that i can’t find here in my country , i Just have one little problem , some of formulas use Urea , Ammonium and Nitrate to offer N to soil or potting media , but your software don’t have any field to set amount of Urea .

    Please consider to add Urea in next version of your useful software .
    Your software help me to mix fertilizers as i need and help me to get good results in soil and potting media and will be greatly improved if you add Urea .

    Again Thank you for your useful software and Great and kind Support to your free software .

    Best Regards

  • July 27, 2017 @ 9:31 am

    I see on the description that fertilizers can be calculated in mmol/L but I can’t seem to find anywhere on the calculator to adjust these settings. Also, if you set the weight output to ounces it still shows grams on the results page. Thanks again for such an amazing contribution to the industry.

    • admin
      July 27, 2017 @ 10:50 am

      You can convert to mmol/L by clicking the “mM” radio button in the “Concentration Units” panel (around the middle of the “Main page” tab).

  • September 13, 2017 @ 10:21 pm

    Thank you for the tool and all the hard work you put into it.
    I am hoping to use it for Fogponics calculations. I will let you know how well it turns out.

  • September 14, 2017 @ 1:36 am

    ! Cannot execute “C:\Users\ilib8\AppData\Local\Temp\Rar$EX19.862\HydroBuddy_Windows\hydrobuddy.exe” how can i fix this i try to download this and after i run the application this will result….tnx in advanced pls hepl me

    • admin
      September 14, 2017 @ 6:56 am

      You need a 64-bit Windows machine. If you want to execute on a 32-bit Windows machine you’ll need to compile the program yourself from the github source.

  • October 9, 2017 @ 10:40 pm

    The latest windows download has all the dbf files named differently so it won’t use your old files unfortunately. Just an FYI, not sure if that was intended but it sucks.

    • admin
      October 10, 2017 @ 2:14 pm

      Yes, I needed to do that because the dbf files for windows/linux couldn’t have the same names due to some changes made in the library I used to read/write them.

  • October 23, 2017 @ 11:45 pm

    Not installed. pls help.
    getting message
    The version of this file is not compatible with the version of Windows you are running. Check your Computer’s System Information to see weather you need an x86 (32 bit) or x64 (64-bit) version of the programme and then contact the software publisher.
    Balkar Singh

    • admin
      October 24, 2017 @ 8:11 am

      You need windows 64 bit to use this program. If you have windows 32 bit you need to compile the program from source yourself.

  • October 26, 2017 @ 2:44 pm

    Great program, thanks very much for making this! I have 2 small suggestions to consider adding as features in the future:
    Strength setting:
    Say you have a recipe you like but you want to do a 75% strength feeding, it would be awesome to have 100% be the default setting in a text box somewhere and have the ability to enter in any % and have the recipe adjusted. Maybe there is another way of accomplishing this that I haven’t figured out. The second would be something to manage PH. I know that my water requires 2.5ml per gallon of my sulfuric acid PH down solution, having that along with the ingredient amounts would be cool.

  • November 28, 2017 @ 7:57 pm

    Hello I’ve looked everywhere for a video on how to use this and can’t did 1? YouTube Google anywhere. I’m try to do the copy commercial nutrient formulation ad anywhere ll the info and always says there some sort of problem. If I could just see someone using hydro buddy once I’d probally be set. Any help is much appreciated thanks.

  • December 17, 2017 @ 5:18 am

    Can you please add anhydrous calcium nitrate in substance selection

  • January 6, 2018 @ 6:41 pm


    First of all I’d like to say that the program is really an indispensable (and incredibly handy) tool for making custom fertilizer mixes and it’s one of a kind. The ability to account for the variations in the tap water makes it even more awesome (I’m lucky enough that the local municipal water company has complete trace element analysis of the tap water publicly available) so it allows me to make the dosing even more precise. I noticed something strange though. I saved the nutrient contents of my tap water into the program’s database. However when I closed and re-opened the program and tried to load back the nutrient contents of my tap water, nothing happens. And yet the data is definitely in the database, I checked it myself. Any ideas?



  • Lee Boon
    January 22, 2018 @ 10:19 pm

    How do I create an account and sync my formulas on all computers that I used?

    • admin
      January 24, 2018 @ 11:24 am

      HydroBuddy does not provide this functionality.

  • February 22, 2018 @ 11:13 am

    Great program. However I am not being able to use it. I have entered Target ppm values , and also the chemicals i need to use. However, when I want the calculation to begin I get en error message saying at least one substance I selected must contain each elements of which I desire a non-zero concentration”. What does this mean ? I have done all calculations by hand and I have managed to grow tomatoes well.
    Also, what should I do if a chemical I propose to use isnt in your database ? Specifically, I have been using Zinc Sulphate Heptahydrate ZnSO4.7H2O but I cant see this chemical on your list.
    My third question – I cant make head or tail of what this Iron Chelate business is. After all, all that I have read says Ferrous sulphate is soluble, so what is the problem ? nevertheless, I got my daughter to get me a bottle of iron Chelate 10% made by “grow More, California”. It also contains nitrogen 3% and potash 1%. It is an HEDTA-Chelate. I do I compute the weight in grams I should use in 45 litres of water if a need a ppm of 5 ?

    • admin
      February 23, 2018 @ 5:55 pm

      If you want answers to these questions please feel free to book an hour of consultation time through the website’s booking service.

  • March 27, 2018 @ 6:20 pm

    I am currently using a liquid Calcium nitrate (51%) from Van Iperen in a commercial hydroponics system. I currently dose my salts into the line with a bypass fertigation system. I do dose my A & B solutions at different ratios due to the high concentration of the liquid calcium nitrate that i use. Is it possible for Hydrobuddy to calculate this difference?

  • August 5, 2018 @ 9:17 am

    Hi Daniel, thank you for the great software ! I wonder if there’s other pre made nutrient formula to add in the database ? Like melon, there’s only one recipe from Douglas Peckenbaugh, i wonder if you have other recipe. Thanks !

  • November 27, 2018 @ 9:58 pm

    I’ve added custom selection in the database, the result shows. But in the database the substances are gone. The pictures are shown in the link below.


    Please advise. Thank you very much

  • February 19, 2019 @ 6:43 am

    Hi Daniel,

    Great work – I have built a rather large spreadsheet that does a similar job for me (including water report data), and since finding your application have been using HydroBuddy as a reference to check my maths. :)

    I had a few questions, but answered most of them poking around the program (such as accounting for acid dilution using the ‘purity’ parameter).

    One suggestion, which I’m sure you’re already on: When editing a substance, P2O5 and K2O can be selected in place of P and K (which is great for us who rely on European NPK labelling). Is it possible to have this option available on the main page as well? This currently seems to be hardcoded to P and K, which makes the maths awkward (and therefore errors more likely) for those of us who are used to working with P2O5 and K2O figures.

    Best regards, and please do keep up the excellent work.

  • February 25, 2019 @ 6:55 pm

    Hi, would you consider letting us save formulas we prepare from substances? Right now we have the ability to save/add target ppm for formulas but we don’t have a way to save preparations done from the substance list in the program to recall them quickly once we have calculated them. I know we can export the results to csv but would you care to implement a way to save our custom formula mixes so we can quickly compare our various DIY formulas right in the program?

  • April 4, 2019 @ 4:50 am

    Hi Daniel. I have downloaded the Hydrobuddy software in my 64-bit Laptop.
    When I try to view the formulations, water quality files, I am not able to open them.
    System is displaying the message as “The files have some error in opening”.
    Can you please help me out.?

  • April 11, 2019 @ 12:28 am

    thank you for best nutrient calc

  • July 1, 2019 @ 10:26 pm

    Hi Daniel, at the first i should say congratulations for your great work, it is a pretty, light and useful software. After that, i have a question and maybe a suggestion, do you think about contributing in making a new software that can calculate all fertilizers needed for a specific crop (according to market demand), that can considers all the required factors for modeling greenhouse conditions in anywhere. Actually specific softwares for designing hydroponic solution for each crop. For example a software for rose or cucumber nutrition that can suggest all needed fertilizers for making nutrition solution considering the hydroponic system, grows stage, season, sun light, temperature and all other involved factors. Intensively i am wait for your answer. Best regards.

  • September 30, 2019 @ 7:10 am

    Hi Daniel, thank you for creating and maintaining HydroBuddy!
    I’m on Linux, and every time I launch HydroBuddy, it says “Database not found” and asks to show him the folder with the database. How can I make HydroBuddy remember the path to the database? Thanks!

  • February 3, 2020 @ 11:25 pm

    Hi Daniel, thanks for sharing.

    I don’t get the same amount of final product when I switch from “Concentrated A+B Solution” and “Direct addition”

    On the first case I get twice as much as the second with the same total cost of salts.

    The parameters I used

    – Tomato stage 1
    – Stock Solution Volume = 1000
    – Liters
    – Concentration Unit = ppm
    – Mass Unit = Grams
    – Concentration factor = 1

    Result for A+B
    Cost = 133.5
    Values calculated for the preparation of 1000 liters of A and 1000 liters of B solution. Please use 1000mL of A and B within every Liter of final solution

    1000 liters of A sol + 1000 liters of B Sol = 2000 Liters

    Result for Direct Addition
    Cost = 133.5
    Values calculated for the preparation of 1000 liters

    Total of 1000 Liters.

    Please let me know what I’m doing wrong.

    Best regards


  • February 7, 2020 @ 1:06 pm

    Running Ubuntu.

    nothing happens when I try to execute the program.

    I ran chmod +x hydrobuddy

  • February 10, 2020 @ 8:14 pm

    I am trying to take my expensive nute formula…Botanicare, cyco, cutting edge etc and figure out what and how much raw materials I need to mix to replicate them.

    I have the %s from https://agr.wa.gov/departments/pesticides-and-fertilizers/fertilizers/fertilizer-database/fertilizer-company-lookup

    How do I use the information I have in conjunction with the program to find the data i’m looking for?

  • March 27, 2020 @ 2:50 pm

    thanks a lot
    god bless you

  • […] changes through the years. The latest version as of May-24-2020 is now 1.70, which you can download here. This new release implements some important updates and modifications. In this post I will write […]

  • Nehan
    May 25, 2020 @ 9:46 am

    Hey, I just wanted to thank you for all the effort you’ve been putting in. It’s really tremendous!
    I’m trying out 1.7 on Ubuntu 20.04 and get an error after I attempt any calculation.

    “Index Out of range Cell[Col=1 Row=17].

    Press OK to ignore and risk data corruption.
    Press Abort to kill the program.”

    The Row is always the last one there is and it doesn’t show anything in the “Gross Error” Column of the PPM breakup on the bottom left.

    Any chance there’s something I’m doing wrong?

    • admin
      May 25, 2020 @ 9:57 am

      Thanks Nehan. I’m not getting any errors when doing calculations on Linux Mint 19.3 xfce 64-bit. Concentrated and “direct addition” calculations seem to work fine. Let me know the exact setup you’re trying to run. Please note that databases from previous versions are incompatible with the current release so you’ll need to use the DB files that come with the program.

      • Nehan
        May 26, 2020 @ 9:45 am

        Hmm… I’ve removed the folder and re-extracted the files. It seems to be working fine now.
        Let me see if I can recreate it.

  • […] no nitrogen) coupled with a source of nitrate, like agricultural grade calcium nitrate. You can use Hydrobuddy – my open source hydroponic nutrient calculator – to figure out the nutrient […]

  • Stefano
    June 26, 2020 @ 6:40 am

    i’ve noticed that if i change the value of the parameter “density” in “substance selection” the mass of addition remains the same. In other words if i deselect ‘Liquid’ checkbox or specify any value the result it’s the same. I use Linux Ubuntu Mate 19.10 and Hydrobuddy 1.7 (it’s the same at least with 1.62 version).

    • admin
      June 26, 2020 @ 7:55 am

      Thanks for your comment. The density parameter is only relevant if you check the “Liquid” checkbox, otherwise it is disregarded and calculations are done for a solid.

      • Stefano
        June 26, 2020 @ 9:26 am

        Thanks for the quick response.
        The problem is that if i check the ‘liquid’ checkbox specifying the density, the mass of addition in grams is always the same (as if the density would be always 1, i think). If i also check the “calculate liquids in mL” checkbox, the addition is expressed in mL and it change according to the density (correctly). So it seems that it’s not possible to know the mass of addition in grams for a liquid fertilizer, considering that the density parameter doesn’t affect the results.
        I hope I explained myself, I am not a native English speaker :)

        • admin
          June 26, 2020 @ 1:03 pm

          The calculation of a liquid addition in grams does not require the density, so it is ignored when you do not require the results in mL (note that the composition values that you enter are always assumed to be W/W% values). The density is only used when you check the “calculate liquids in mL” as the mass calculated need to be converted to a volume using the density.

          • Stefano
            June 26, 2020 @ 1:31 pm

            Thank you very much.

  • Ravi
    July 23, 2020 @ 11:00 pm

    Hope you doing good.
    Many Many thanks for the software. It’s just awesome.
    This software is really a gift for every hydroponic user. very simple & easy to use.
    Really appreciate your efforts. The most important you are giving this free of cost, really hat’s off man.
    I would only request you to list the chemicals to be added serial wise, means if solution A have 3-4 chemicals then which should be added first that is the only confusion.
    Thanks again for helping. I would donate you for keep going.

  • Bubuking
    July 27, 2020 @ 9:11 am

    It would be useful if the algorithm preferentially used the cheapest fertilizers to achieve the target formulation. For example, I use calmag additives, which are much more expensive than calcium nitrate and I am forced to manually recalculate the mass of additions to obtain the same fertilizer using less additives.

  • Stefano
    August 26, 2020 @ 7:51 am

    Linux link broken.

    • admin
      August 26, 2020 @ 8:06 am

      It should work now.

  • Cheeba Pot
    September 10, 2020 @ 11:25 am

    Been looking for some answers till I finally came across your blog. Thanks for the post. Really interesting

  • mehdi bassou
    October 11, 2020 @ 3:58 am

    We need pH estimation on hydrobuddy

  • Ben
    October 14, 2020 @ 10:00 pm

    Hello, Daniel!
    Great work, good program. I was sad after building a new workstation and HydroBuddy stopped working. It would give me an endless loop of the error message for missing databases no matter how many times I pointed to them. I tried every compatibility mode available, changed screen resolution, nothing worked. Until now. I tested every setting and discovered that in Compatibility > Settings, checking the box for “Reduced color mode” and using 16-bit color while also unchecking the box for “Disable fullscreen resolution” managed to get it working again. With my old data!
    I only post this so anyone else experiencing the same issue can have a potential solution.
    Super happy to have it back.
    Thank you!!

  • zouari slim
    December 13, 2020 @ 9:56 am

    je veut utiliser le logiciel hydrobuddy pour des raisons aquademiques mais je ne peut pas alors comment faires

  • joe
    December 27, 2020 @ 8:49 am

    the windows link is dead. do you have a mirror?

    • admin
      December 27, 2020 @ 7:53 pm

      I just tested the windows link, works just fine for me.

  • Miguel
    December 28, 2020 @ 2:08 pm

    Does not work for me

    • admin
      December 28, 2020 @ 5:47 pm

      Please let me know what error you are getting so that I can debug, the link works correctly for me (just tested again). Bear in mind that chrome will want to block any zip/exe downloads by default, you need to click the file and then click “keep” in chrome for the download to work properly.

      • Ann
        January 3, 2021 @ 7:27 am

        I do have the same issue, i cant download the programm.
        If i click on the link, the browser indicates it loads something and loads and loads and loads (same in firefox, chrome, IE and same with the linux link aswell!)
        If i open the link in another tab, the new tab is loading forever.
        if left click and “save target…” the item will be listed in the downloadlist of my browser (firefox) BUT it loads and loads and loads forever and i wont get it downloaded.
        So no error messages, but just infinite loading.
        If you need more information, i am a user from germany and as mentioned tried it with several browser, also i tried it also with deactivating all possible blocker, firewalls, virus scanners and such.

        • admin
          January 3, 2021 @ 8:32 pm

          I am sorry to hear you’re having issues with the download, sadly it’s hard for me to help you solve them since I cannot reproduce the problem. I just tested it from a couple of different Windows computers on edge and chrome and had no issues downloading, there also seem to be no error logs on either the site or even the server. You can also build from the github source using Lazarus if you’re having trouble downloading the binaries from this page.

          • Jim
            January 19, 2021 @ 10:58 am

            I originally had the same issue in chrome but the right-click open link in new tab worked.
            Just started playing with the program but so far it looks good.

  • Ann
    January 3, 2021 @ 11:38 pm

    Thanks for your answer.
    I tried a little bit more stuff to find any reason on my computer that causes the issue.
    And as it seems i found it.
    I had the “Internet Download Manager” installed on my computer but the addon to use it was only installed in google chrome not the otherbrowsers and it even wasnt started.
    I dont know why but deinstalling this stopped the infinite downloading issue and i could download the zip. I really dont get why it blocked the download in every single browser without the addons and without the programm being started.

    Maybe that answer can help others with the same problem and the same programm on their computer or other download helpers that interferes with the download.

    • admin
      January 4, 2021 @ 11:33 am

      Thanks a lot for posting your solution! I’m glad to got it solved and hope it helps others solve issues as well.

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