Paul B, seems like I always learn something useful every time I've read your thread over the years. One of my pink torch coral colonies (actually now two colonies since one big piece broke off and I put that at the other end of the tank from the original one a few months ago) has been mostly retracted for days. Couldn't figure it out because my other torches were doing fine, but the pinks were unhappy. I just turned my lights on early and, bingo, there's black sponge growing on both colonies. Once I finish my morning coffee, I'm going to expose both to air and then scrub them outside of the tank. Interesting that there's no sponge on the other torches.