Two weeks ago, my Bubble Coral started showing stress. A week ago it started deflating. I could see the skeleton coming out of the coral mouth. I thought it will die for sure, It did look terrible. I used Active Carbon by Rowa, and already after 4 days the coral looked regenerated (as you can see in this photo above). It is very good running Active Carbon 3-4 times a year, to prevent organic build-up.
This recently introduced Clavularia coral started showing off lots of green color. Soon enough it will become totally green. Can't wait ;-)