My Duncan Coral Head is Peeling off

[JoeyClownFish]

About 3 months ago I got a Duncan and I noticed today the head is coming off. I spot feed them and they love it and are always open. Even the one with the head coming off. The tank has gone to some parameter changes as I been really working on my dosing and kinda micro managing element but not moving stuff or adding equipment. MY HANDS HAVE NOT BEEN IN THE TANK

Do you think I can take the head of the Duncan and glue it to a frag-plug that it will regrows its base?

My parameters are
alk. 210
cal 430
mag 1355
nitrite .3
nitrate .20
phos .2

 

[shred5]

You have a little algae problem. When Algae encroach on a coral they can push the flesh back.

I am not sure what your is under but they prefer lower light.