Well, I've done it this time. My 55gal had some algae, and I saw some stuff at Petsmart that said it would rid the tank of algae without harming plants or fish. Unfortunately, this was also at a time when a lot of things were going on, so didn't have time for the tank. Before I knew what was happening, I had lost several fish, all my mystery snails, and 75% of the plants in the tank had melted! I'm assuming it's the !%*& stuff I put in the tank. The kh and pH went thru the roof. I'm doing massive water changes, using part RO water, so will see what happens. That's what I get for taking the easy way out.