Favia skin peeling

[Matt Bravo]

I was looking at my reef today and realized this favia looked like it had come sand on it, I suspected maybe my fish spit some sand on to it. I was blasting it off and realized the actual flesh starting coming off. There have been no light changes or flow changes. I’ve had it for 2 months already and never showed any signs of stress. All other corals are doing well. Any idea what could cause this and how to save it?

Nitrates <12
Phos .06
Calc 440
Mag 1380
Alk 11

 

[Mr. Mojo Rising]

The pic is way too blue to see. Turn down the blues and turn up the whites so we can see.