Should I use chemi clean? That orange slime is everywhere now and I saw red cyano aswellI agree with the other comments. Probably Cyano Bacteria. I've been having some problems with it in my sump and a little bit in my sand bed. Though I'm no expert and I think you should ask more experienced reefers for help; with your sump, I would manually remove it during a water change. That has worked for me. you could also cover it with something to prevent light, because the algae will eventually die as they are photosynthetic. I dont know how to get it off of the coral though. Sorry, wish I could be more help.