OK. This thread (like any other) will be closed if civil conversation can't take place here. It would really be a shame, since there is certainly value in discussing an agent that might posses some beneficial anti-algae properties.
Look, constructive and useful discussion in an open forum can only take place within a framework of mutual respect. One can emphatically disagree with someones position without resorting to a personal attack. The best way to do this is to present evidence to support one's position.
Edward's argument (potential harm to animals) is poorly presented, but does raise a valid concern. With more careful wording, it might have encouraged a healthy discussion about the potential toxic effects rather inciting an emotionally charged exchange. We should all keep in mind that a remedy at one concentration is often a poison at another.
I happen to agree with Cavan's argument that we should all be focusing on providing conditions that don't favor the growth of algae. Even so, it doesn't hurt to investigate the benefits and limitations of a potential algicide. I frequently use a short course of Excel or erythromycin to restore things to a stable, healthy condition.