Shango, Like I said before, I don't know how the live stock would react. It wasn't a problem for the snails in there though :) I didn't really care much about them anyway :P I guess the only way to test would be to try it out on an isolated shrimp. If you think about whats involved it's hard to say how an underwater bug would react. Someone who knows can correct me if I am wrong but I think all thats happening is we are making lots of O2 and oxidizing/bleaching the algae to death. H2O2 is, after all, a very strong oxidizer. I would guess that because of algae's relatively simple cellular structures they would have no defense against the O2 oxidization. All I know is the algae died and I was happy :) It worked very quickly the algae was dead after the treatment finished. Actually it was kind of neat to watch because the H2O2 turns the tanks into a glass of bubbly so to speak. Bubbles all over the place. Lasted for about an hour I would say. -Bryan _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member