I also have this lethal sounding stuff, did you notice "is known to the state of California to cause cancer" on it too? That scared me a lil.

Does an excellent job on green/brown long hair algae which I am unfortunately blessed with. At normal does it freaks the fish, they all school and look scared after adding, then about a month later when it's worn off I need to add it again. I was thinking maybe if I add it regularly it would eventually just kill all the hair algae off altogether... wishful thinking???

I also have this lethal sounding stuff, did you notice "is known to the state of California to cause cancer" on it too? That scared me a lil.

Oh my goodness, no my bottle doesn't say that - oh cor I don't think I'm going to use it again!

I gather quite a few aquatic medications and stuff are known carcinogens

Just about everything is harmful in some way or in some conditions. Most foods contain carcinogens, air is toxic and contributes to aging, table salt is made up of an extremely corrosive and poisonous gas and a metal that explodes on contact with water...Anyway, just because it says it's a carcinogen doesn't mean it's dangerous. All that means is that when injected into lab rates at hundreds of times the dosage you're normally going to be exposed to that it caused an increase in the percentage of rats getting cancer.

I use this product for algae control it is safe effective cost wise for the job it does very good here is the site http://www.algone.com/