Hey Susan, I was going to go dose two of my algae-infested tanks when I got home until I read your post about this; could you please expand on your experience a bit? Was the pot. perm. in your tank, and how come? What was the H2O2 supposed to do in this case, and was it more than the one oz./10G that Tom mentioned??? I too would really like to knock out some amazingly fast-growing hair algae but would really prefer the critters in the tank survived the treatment... ;+) Thanks! Connie ----Original Message Follows---- From: "Susan Welenofsky" <welenofsky@comcast.net> I managed to kill almost every fish in my tank once with H2O2 after neutralizing some potassium permanganate. _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member