Well, I'm dealing with green water in my current little 10g.
I'm also going to be getting 55 at some point in the near future from a friend of mine, and figure I can put a stop to the problem before it even starts in that one.
I do know that there are underlying reasons for green water in the first place, which should be resolved instead of using "band aids", but some other people seem to be of the opinion that UV
lights are a godsend.
Why do you say they're a waste? Is it because other remedies can be used in most sitiations, or you just don't think they work? Or some other reason?