Not Sure what i have going on...

[Signalhead]

Good afternoon,

Not sure what type I have (Name or coral type) I just noticed today to stalk is starting to turn black. All parameters are acceptable except the CA. On average is in the 380 range so I dose once or twice a week to raise it to the 420/ 430 range. The water circulates in an alternate mode (on/off) 27/7 and it's all moderate flow and its keep at 78°. Its this thing dying? Or its normal?

 

[Signalhead]

Any ideas?

 

[timrocks311]

its a hammer coral. it looks happy and normal to me in the picture. they aren't entirely fleshy. the dark part is the hard stem.

 

[Signalhead]

Thank you for your help!