I've had this coral for at least 12 years, it grew into this beautiful dome from a little frag. I love the little cave under it as some of my fish like to hang out under there, so I like to place it as in the first photo with the cave showing. Last fall my stand failed and I had to take the tank down in a hurry; for the last 9 months the corals were in a temporary tank with marginal water quality while I was getting a new tank. This one developed some reddish brown patches as shown. I've removed a few small pieces of bubble algae from the dead areas. One of my other favias had a much worse case of this in the temporary tank and had to be fragged. This one is now in the new tank with good water quality but I'm not sure if these spots will heal. I could just leave it as is and observe it, or even turn it so the dead areas are not showing (as in the second photo), but I don't want this to spread and kill the coral, and I would prefer not to frag this one too. What would you do? Appreciate any advice!
