My hammer is not extending anymore.

[Notsolostfish]

I bought a hammer coral 4 weeks ago from my lfs. And the moment i put it in my tank it was extending no problem. Literally like 4 days ago i dont know what happened to it it start retracting for no reason and second day it stopped extending. My calcium is 450. My phosphate and nitrate according to hanna checker they were 0. But i was feeding heavy and now im dosing nitrate and phosphate its still closed. I truly love my hammer, and i dont want to lose it. Flow didnt change.

 

[tmccaff]

Did you acclimate it to the lighting? Check flow as well. Phosphate and Nitrate at 0 could be issue.