The algae on the glass in my 55 is getting out of hand. I just scrubbed it yesterday and it already needs done again. I already have cories for the bottom so I don't want a bottom fish (yes I know cories don't eat algae, that was not the point of getting them). I like the idea of one giant snail, but don't know how good at algae eating they are. Nerites are my next choice and I was thinking like 4 would be good for a 55.