HydroBuddy v1.9, MacOS binary, new EC model, many bug fixes and more!

HydroBuddy v1.9 on MacOS BigSur

Today I am releasing a new version of HydroBuddy (v1.9) which contains many suggested and needed improvements from the previous version of the software. In this post I want to discuss the changes within this release and how they will affect the way things are done in the program. Some big changes have been implemented so make sure you go through the list below if you want to use this new version. Thanks to all of you who contributed your suggestions about HydroBuddy and/or reported bugs to me.

One of the biggest changes in this release, the return of precompiled MacOS binaries.

Here is the list of changes in this version:

  • A MacOS binary compiled in Big Sur 11.0.1 has been released.
  • Ability to make any formulation the “default” formulation. This selected formulation is loaded when the software is started.
  • The LMC conductivity model has now been replaced with LMCv2 which is an important improvement. See here to learn more. The LMCv2 model now adjusts conductivity based on each specific ion’s charge and the overall ionic strength of the solution. It now includes no arbitrary terms.
  • The treatment of liquids/solids in the program has now been changed. Instead of specifying liquid or solid (and the program having to make assumptions) users can now select whether the percentages and substance amounts are going to be either in g and w/w% or in mL and w/v%. This should simplify the interpretation of results and the addition of substances.
  • An additional column has now been added in the results page to specify the unit of the amount being calculated. When a user wants a substance’s contribution to be calculated in mL, the appropriate unit will be shown here.
  • When adding a new substance, all fields are reset to null values (previously the program kept the values from previously opened/updated substances).
  • Density has now been eliminated as a variable used in the program since it is not needed if there is no cross between w/w% and w/v% calculations. It is only kept in the “Copy commercial nutrient formulation” dialogue.
  • An error where P and K were mixed up in the product comparison window of the “Copy commercial nutrient formulation” function has now been fixed.
  • The wording of options in the “Substance selection” dialogue has been changed so that the buttons better describe what they do. For example the “Delete” button has now been changed to “Do not use”.
  • Two buttons have been added next to the EC model prediction in order to allow users to increase or decrease the EC by adjusting all nutrient concentrations by +5%/-5%. This will allow you to see how nutrient concentration changes affect conductivity in a straightforward manner.

The above modifications are now committed to the github repository as well. Feel free to take a look if you’re interested in how any of the above variations were coded into the program.



  • Hydroboy
    March 28, 2021 @ 1:05 am

    Hi Dr. Fernandez,

    I have been using this when using my nutrient solution on previous versions of hydrobuddy. Does this procedure still holds with version 1.9?

    “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”

    Thank you.

    • admin
      March 28, 2021 @ 7:31 am

      Thanks for commenting! That is not correct, in the current and previous versions, you would add 10mL of A and 10mL of B per 1L of solution, NOT solvent, so this means that you would have 10mLA+10mLB+980mLWater = 1000mL of solution.

      • Hydroboy
        March 28, 2021 @ 9:03 am

        Hello Dr. Fernandez,

        I took this quote from admin in the thread blog of main hydrobuddy, this is why I’m clarifying and confuse now. And i have using the below in mixing my concentrate solution to the water.

        April 27, 2014 @ 10:23 pmReply
        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,


        • admin
          March 28, 2021 @ 10:14 am

          Thanks for your reply. Yea, that changed in the 2016 updates. Everything is now calculated per volume of final solution, not volume of solvent.

    • D
      August 14, 2021 @ 10:44 pm

      Hello Dr. Fernandez, I could use some help. I’m confused why hydrobuddy tells me it something needs to be added to the substance selection list to provide a nutrient and then it doesnt use the substance. For example, I wanted Fe at 5 ppm, it tells me to add something to provide Fe, when I add it, it doesnt use it, shows zero on results page, but the Fe will be at 5. But if I remove it, it tells me I need it. Also, is there a way to get the app to recognize and use two inputs to meet my needs. For example if I want 300ppm of K, but need S and P. If I use K2so4, MKP, and mgso4 (to meet Mg needs) and have S set as the nutrient it can put at any level, instead of using what I told it to, it may use only mkp and omit the k2so4. I would want it to split the need for K between the k2so4 and MKP. Is there a way I can make the add do that?

      • admin
        August 17, 2021 @ 10:36 am

        Thanks for commenting! This might be problematic when you have a water analysis you want to include. HydroBuddy needs substances for everything that is not zero to be included, even if adequate levels from water are available. If this is your case, then just including the substance and having HydroBuddy ignore it might be the only solution at the moment.

        About wanting to include a given substance and split half way with another, the problem might be that there are too many substances HB can get the requirements from, so it might be getting confused, try using fewer substances or, you can try using the “Set amount” button in the substance selection screen so that HB is forced to use a minimum quantity of some given substance when doing the calculations. In the end, HydroBuddy tries to find the closest solution, but might struggle if too many potential solutions that are similar in error exist. Reducing your list of substances to the bare bones necessary to meet the requirements usually helps eliminate issues of this sort. It also helps if a better selection of substances that better reaches the target formulation is made.

        I hope the above helps you out!

  • Chivas
    March 31, 2021 @ 7:59 am

    Thank you for the update Daniel. Will this version still be compatible with databases from version 1.80?

    • admin
      March 31, 2021 @ 8:50 am

      It should be compatible! Thanks for commenting!

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