Testing Water in Our Aquaponic System

Hi Everyone. I get a lot of questions about how I maintain the proper water chemistry so I’ll show you what I do in my system. You can see here that my tomatoes were suffering from an iron deficiency. At the same time, the lettuce was also suffering. The nice leaves are the newer growth after I added some iron. I will admit that I don’t check the water very often, but I’ve found with my systems that keeping a fairly low fish density helps a lot – which keeps the various levels lower than most systems. First I’ll start with a standard fresh water test kit which checks the pH, ammonia, nitrites, and nitrates. This one is made by API and is normally used for ponds and aquariums. It's important to accurately fill each tube so that the readings aren’t skewed. It’s also important to follow the instructions and apply the chemicals in the proper order and wait the appropriate times before reading the results. Looking at today’s readings; the pH is right at 7.0, ammonia is at 0.25 ppm, nitrites are low at 0, and nitrates are at their typical level of 5 ppm. Next is checking the iron level. I found this kit that works well and is simple to use. You just add a spoonful of powder, a couple of pipettes off water, stir it up so the powder can dissolve, and wait a little while. It comes with a color scale that you match to the water. I’m currently at 0.4ppm and usually like to be around 1ppm. To increase the iron levels, I add this iron chelate to the buffer tank. This is a good spot to add it since it’s pumped directly into the grow beds and helps to dilute it before it makes it back to the fish tank. About once a month, I’ll add some liquid seaweed extract to help replace some of the trace nutrients. It will turn the water brown but will eventually clear up after several days. The pH in a healthy system will continue to go down. To help buffer the water between 6.5 and 7, I will add some powdered limestone, or on occasion, some potassium hydroxide. Thanks for watching. If you enjoy these videos don’t forget to subscribe and join us on Facebook!