Ello, all. I've recently started going to plants as i came from a desert/rock community in my tank. Buying a few plants at a time from the usual stores and wanted to help them grow Without putting CO2 injectors in the tank. I bought the API Leaf Zone substance and i put the correct dosage in the tank. (90Gal) says to use it once a week, well i came home about 4 hours latter and my Silver tip Shark and Pictus catfish was dead. My other Pictus was still alive and all the other fish seem to be doing just fine. Anyone have any input on this type of substance or recommend one without going into CO2? Thanks again.