The stuff he put in was kents freshwater. I'm assuming all his parameters are, were stable. He uses those test strips, said the water went way below what the strip would read. May have been a bad strip???? Just the Idea of putting fertilizer in a tank scares me. I don't even put much in my garden. But my new plants are looking kinda rough. course I need more light too. I'm learning. I've only got 1.2 wpg,but working on that. anyway, I thinks ferts may help, if they don't hurt my fish. They say it's a pain keeping both in a tank.