Is the water in your aquaponics system slowly turning basic or getting high pH readings? Some common sources of basicity are the build-up of carbonates (CO32-) from limestone, bicarbonates (HCO3–) from hard tap water, or excess phosphates (PO43-) from over-fertilization. Before you ask how much vinegar you should use to lower the pH of your water, let’s go over some remedies and the science behind these solutions. I will help you better understand what to do when your aquaponics water becomes basic.
Why Using Distilled White Vinegar and Citric Acid Are Not Advisable
Using citric acid or vinegar to lower the pH of water for aquaponics might cause more harm than good to your system for a number of reasons. Vinegar is a mixture of 5-8% acetic acid and organic compounds that might act as stressors for your fishes. When acetic acid reacts with water and dissolved oxygen, it consumes oxygen and turns it into carbon dioxide and water, which makes the water more acidic. On the other hand, citric acid is a common organic herbicide that would kill your plants and bacteria in the system.
Basic Solutions For Basic Water
Your aquaponics system will slowly maintain and regulate itself to a pH between 6 to 7 if all biological processes are balanced properly but if you ever find yourself with a pH value above 7, here are several solutions that you could try at home:
Use pH Down
pH down is a safe and tested choice for lowering your pH, most of which is phosphoric acid. It is safe to use commercially available freshwater aquarium pH down or general use hydroponic pH down. The phosphorus in the pH down is also utilized by plants as well as algae, so it is safest to use pH down sparingly to avoid algal growth while still feeding your plants with extra phosphates to use for their growth.
Add Neutral pH Water
Personally, I top off my aquaponics water with prepared pH neutral water daily and this dilutes the amount of carbonates and hydroxyls in the water bringing my system’s pH closer to 7. You can prepare pH-neutral water by using pH down and setting the water aside, collecting rainwater, or simply setting aside a container of tap water exposed to air, this will react with the carbon dioxide in the atmosphere causing the water to become more acidic over time.
Read more about: How To Fix Hard Water In Fish Tank
Let Time Do The Work
Time may be the most stable solution to an aquaponics system. As your aquaculture system produces ammonia from fish excretion, the nitrogen-fixing bacteria found in the water will begin to oxidize and process the ammonia to compounds that are readily available for your plants to utilize. This nitrogen fixation done by the bacteria is a process that will make your system steadily become more acidic over time if your system’s nutrient balancing is correct.
Find more information about Your Step By Step Guide To Unionized Ammonia Calculation
Last Few Tips
As you go through the process of balancing your system’s pH levels, it is important to take note that any compound or solution that contains sodium is detrimental to plant root systems. Any sudden change in water quality parameters including pH could also cause fish kill and stunt the growth of your plants, so it is better to adjust your parameters daily until a balance can be sustained over the long term.