I`m going to go another direction. I think it`s the dreaded Brown jelly disease. It`s a disease that will kill the individual heads. When you see one going bad you have to immediately break that head off and dont wait for it to deteriorate all the way. It happens to alot of LPS corals. Here is an article about it.
46g SW bowfront, 196W Coralife PC fixture, 2x 100W heaters on a Johnson Controls controller, AquaC Remora Pro skimmer (Mag3 pump), Marineland Magnum HOT cannister, Marineland 100 Penguin Biowheel (for transfer to QT), and a Koralia 2.
70 lb of live rock, and 4+" sand bed.
Various nassarius, turbo, trochus, astrea snails, a Tongan conch, and 4 small hermits, as well as a skunk cleaner shrimp.
3x Blue Chromis, Bangaii Cardinal, O.Clown, and a yellow clown goby.
Mostly LPS corals, with a few SPS thrown in high in the tank.
I have always found it better to remove dead portions on lps corals. It typically will spread other wise.
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*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,