Help With Deepwater Acro

[Drock169]

I dont think less light is the solution in this case. They typically bleach out if they are getting too much light, not brown out. I would dip it in something like Revive, see if anything comes of the coral. Have a good look for at the base of the coral for little square bite marks on it. Because it's just a single colony affected, my guess is parasite.