I'm not really sure. The first picture is from a system I have just finished cycling in preparation to adding some tilapia into the mix. The other two pictures are from a hydroponics system that has been running since the July 1, but I don't think any cycling has been completed in that bed. When I test the ammonia, nitrites, and nitrates of the second bed I'm seeing 8+, 0, and 0. And pH of both the beds are within range. I don't have a ec/ppm meter. All i have been adding to the first bed is ammonia to keep the bacteria alive while I wait for fish. In the second bed I used Miracle-Gro water soluble all purpose plant food at about 2 tsp/gal. I also have added some iron chelate.