I think Phillip made a very good point about the soft water. I use the Discus buffer but because my water (mostly RO with some tap) is soft already, I do not have to use much buffer to get it stable. If you use no buffering agent it is hard to stabalize the soft water. Thanks for the extreme phosphate warning though. I never imagined it could actually kill the fish. I have tried the peat things and the PH just seems to wander all over. I am suprised to hear about problems with "Waters of the World". I have heard good things about it but I thought it too expensive to be practical. Anybody else use that?