the breadmold stuff erik is talking about i have a bunch of all over my rocks. when i explained that it was black and looked like it had a layer of something resembling the mold found on oranges when they go bad i was told it is black cyano algae and can possibly lead to disease and even death :shock: i have been using the miracle stuff(chemi clean) for about two days now and it is noticeably retrieving. you might want to look into getting some chemi clean(even if it doesnt turn out to be black cyano this stuff works wonders on water quality).

steve