Be sure it's out of the intense light (shaded would help) and very little direct water flow but enough to prevent detritus accumulation. If the polyps will accept foods, feed them meaty items soaked in a marine vitamin high in vitamin C. Also be sure you dose the tank with the vitamin as well. About 5 ml/10 gal
. Remove any carbon/resin products first though.
If you notice any "brown" accumulation you need to syphon it off the coral and out of the tank. Try not to spread it. Sounds like brown jelly disease. You should also do several large water changes with well aged SW
Are they near any other corals and what is the alk