Stylophora problems

[DiverDan358]

Has anyone seen this happen before? It looks like the colony is peeling away from the skeleton. This is a 2.5 yr old tank with numerous sps corals, very low nutrients, metal halides and t5 fluorescents.
We have been dosing with a little NaOH mixed with DI water in a drip to bring up Total Alkalinity.
Any advice is appreciated.

 

[Sallstrom]

Looks like very low nutrients to me. I would try to raise them/stop carbon source if you use that.

 

[Reeves' Reef]

Very low!? Let me think....as I remember my last readings for nitrates and phosphates the best I can read my test kits were; <10 nitrates and <.06 phosphates there about. I dose carbon everyday. Not sure what very low means but that coral is hurting. Mine, not so much.