[lcstorc]

I have been told that when they are dying they will turn grey. Is yours changing color at all? I have not noticed any raised rings, but perhaps it is budding a new branch? Just a guess since unfortunately I know little about them.
My husband came home with it one day then all my reefing friends told me it would die and to keep a close eye on it so it doesn't polute the tank. Well, for some reason it is happy with several new branches and no grey at all. I wish I could be more help, but I didn't notice the new branches until it was obvious that they were new branches so I am not sure what they look like in the beginning.
The one thing I do know about sponges is that they cannot tolerate the air even for the briefest time. When you introduced it to the tank were you careful to keep it submerged in water the entire time? Still if it is not turning grey it is probably ok since that is what I was told to look for on mine.