With me, it was a combination of things. I was overfeeding, I had bought VHO compacts, High phophates as well. Then I bought some mexican turbos, 5 emeralds, two sea slugs (although I think my eel has recently snacked on them) and an Atlantic Blue juvenile tang. I must say, in about two weeks time, my LR is back to its beautiful coloration. I just need to keep feeding normally.