Hammer Coral Peeling

[Baboon7]

Hello I have had this hammer Coral for about 9 months with no issue but recently it hasn't been opening up all the way and today it looks like it is just peeling off its skeleton. it's in an area of low flow right in the middle of the tank. Any ideas?
Alk-9.1
Calc- 450
Mag- 1500
Temp-79
Under 2 AI Hydras *gen 1
2 HO T5s
90 gallon tank

 

[Baboon7]

Hello I have had this hammer Coral for about 9 months with no issue but recently it hasn't been opening up all the way and today it looks like it is just peeling off its skeleton. it's in an area of low flow right in the middle of the tank. Any ideas?
Alk-9.1
Calc- 450
Mag- 1500
Temp-79
Under 2 AI Hydras *gen 1
2 HO T5s
90 gallon tank

 

[WIReefer]

Did it get damaged at all? Have you noticed any slime or brown substance from it?

 

[Baboon7]

Don't see any brown slime on it. Like a month ago a rock fell on it when I was moving around some stuff but it had opened up since then?