i'm still dealing with ugly stage. i decided to clean it off the back and side glass. it was brown algea/dyno not sure. it did bubble, but it was not as thick and snotty like other stuff, came off in sheets. anyway, tank looked like a snow globe after the scraping, the sps coral completely retracted while that stuff was floating around. does that stuff release some kind of irratint in the water or would it just be the friction of the debris hitting the coral? it took about 1 hr for it to be filtered out.