Whats wrong witn my hammer?

[Notsolostfish]

My hammer today, one of the heads not extending. And i can’t tell whats wrong with it. My mag is 1400, my calcium is 430, my alk 8.5. And my ph is 8.2 stable. I feed 2-3x a week. Red sea ab+. And reef roids, reef chilli fed yesterday. Salinity is 1.026. Phosphate 0.18 and nitrate 9.6

I havent done a water change in few weeks, as iv been dosing all for reef, and its been going good. My hammer used to extend BIG. Really cant tell whats wrong with it. I attached a picture of how it looked like but yeah.

and thats the video of how 1 head not opening. Nothing peeking on it. I fed twice, and it was fine yesterday. Do i do a water change? Its been like 2-3 weeks without one. Didnt want to bottom out my nutrients

 

[MoshJosh]

What are N and P? I understand reef roids can increase P quite a bit.

Also, any flow or lighting changes?

Also, any visible pests on coral, stem, or surrounding rock?

Also, any chance the head is splitting? As I understand it these corals can get a bit angry looking when splitting.

 

[MoshJosh]

Double post.

 

[Notsolostfish]

Double post.

I pressed post by mistake twice

 

[kevgib67]

Your parameters look fine. If they were big happy I agree with @MoshJosh, it may be splitting.