The solution ? It is actually very simple. Have a hydroponic growing container in which plants that you “don’t care for” are grown. For example, have a hydroponic growing container in which grass, weeds or other type of “low nutrient requirement” plants are grown. This way, when your hydroponic crop has a solution it can no longer use, pour that solution into your other hydroponic container. Now leave the solution for those plants to take care off for two months. Once this happens, the solution should be very depleted of nutrients and unable to cause any algae bloom of importance.
Even better, the “waste solution” container, can have plants you can use. For example, you can cultivate herbs with low nutrient requirements that are for indoor use and have them as the “byproducts” of your main hydroponic system. It is also excellent for growing grass for any cattle or horses you may have. (below a picture of papyrus, a plant that naturally deals with solutions with low nutrient concentrations)