Hi Dianna, There are several threads last spring in the months of April and May dealing with Excel treatment for algae. Here is one that I did: http://lists.thekrib.com/gsas-member/0804/msg00130.html Here is a very good one on Aquatic Plant Central (APC), its long but a very good read: http://www.aquaticplantcentral.com/forumapc/algae/3806-flourish-excel-got-ri d-all-my.html At two times (2X) normal dosage it took a couple of weeks to clear it up. Excel took care of all my algae except for green dust algae and green spot algae. Mine BBA has never come back, I continue to dose at the recommended rate. I recently picked up some 50% solution biological grade Glutaraldehyde which is the active ingredient in Excel. I will be experimenting with it when my Excel runs out. Roy _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member