Yellow hammer expelling white and brown

[Jorge091293]

Maybe I can get help on this forum 

Had  this yellow hammer for two years all the sudden is not looking good all I changed were adding new leds to my reef but it was doing good under them 
It is the only coral in my tank that is not doing good everything else is opening 

I do see some brown stuff peeling off the skeleton and also white ...   is it releasing zoantheli? 
I moved it to low flow and a bit of shade for now to see how it does 
Any ideas of what it could be 
Calcium 420
Alk 9.8 
Nitrates 6 
Amonia 0

ligthing also showed 

did check all the par on the tank and coral seem to love it 

 

[Jorge091293]

Runing (2) 26 hydra hd 

on a standard 75 gallon 

12 inches above water