Green Birds Nest dying

[Reflective]

Just wondering if anyone knows why this coral is dying? Haven't changed anything in the tank recently. I do have other SPS in the tank and they seem to be doing great.
Temp: 78-79, pH 8.25-8.35, Alk: 8dKH, Ca: 450, Mg: 1230

 

[143MPCo]

What type of lighting and how old are the bulbs if not LEDs?

 

[Reflective]

Pacific Sun T5/LED hybrid. T5's are about 3 months old.

 

[Reflective]

And the white spots started on the base a few days ago and have been spreading.

 

[LetItReef]

Check flow too. Our BN seems to like moderate-strong flow.

 

[Reflective]

Check flow too. Our BN seems to like moderate-strong flow.

I'll try and clean my Gyre. It doesn't look dirty but maybe it's not working as well as it once was.

 

[Stephanie11]

Frag it. I've had a couple birdsnest colonies do that over night and be gone.

 

[jasonandsarah]

99% of the time it starts at the base it's either flow or shadowing imo.
That's of corse assuming you don't have any pest? Any new additions or changes to the system?