Every 6-8 weeks, I post my photometer readings for the aquaponics system water. The biggest change I’ve made this term is using rainwater exclusively. I should also add that I lost a bunch of fish in early February due to an aeration pump failing. Hoping to have more fish in the next week or so. I guess that was a big change, too.

You can see, the nitrate level is a little lower since I lost most of the fish in one tank and about half the fish in the other. The best news is that the sodium is slowly going down since switching to rain water. We’ve been getting some good El Niño rains and I hope that I have enough rainwater to last until next winter to see what it is like to grow with lower sodium levels. Lettuce head quality has improved and I think it’s partly due to the sodium dropping and also because I had to add some potassium bicarbonate and calcium hydroxide to adjust alkalinity and pH since changing to rain water. It will be interesting to see how the growth goes in the next couple weeks. Having the potassium and calcium boost certainly helped and I will keep an eye on those levels. As the sodium drops, I think it will be easier to look at how the occasional additions improve growth. You can also see magnesium is slowly dropping, too. Over time, we will be able to see what the sweet spots are for each of these elements in this system. Like in the case of iron, I made two additions. One in December and one in February to get the iron to above 2ppm. In the future, I look forward to working with some of the newer organic fermented fertilizers to maybe add a boost every now and again to grow a more diverse crop. Is that cheating? Sort of, I suppose. Maybe we add some of this to the fish food formulation. It’s all up for consideration. I’m mostly interested in the health of the fish and the nutrient density of the produce to optimize aquaponics. We already know how water wise aquaponics is. Now, we just have to figure out how to tweak our methods so that we can grow the healthiest food possible. Sharing this information helps us all to see how one system is performing. Perhaps, this will inspire others to share their system info so we can compare notes to contribute to a healthy aquaponics industry.