over the past few months I have had a large welsco open brain begin to slowly peel from its skeleton and no matter what I did I could not reveres or stop the tissue recession, recently it completely let go of its skeleton. The part that is worrying me is now 2 other corals have begun to recede too, a wall hammer and a scoly. all my parameters are stable and other than these corals all others are growing and happy the only change I have made is switching to led lights but as soon as I thought they might be causing this problem I dimmed them way down and switched back to mostly t5's dose anyone have any ideas as to why this is happening?