I just did my first dose of the dry ferts to my tank. I did some tests before the addition for comparison purposes. Everything went up Nitrates, Phosphates, I assume that potassium went up as well (I don't have a test). The strange thing for me is that the iron levels went down to 0. Before the addtion of the ferts the levels were around ~.04 to .05, but after the addition of the ferts (including the plantex which has iron) the water in the tester just barely changed the color. Meaning the levels are at 0.