Danny,
I kinda nuked my old green open brain in my wifes tank one night. I think it was because I poured straight ro/di water on top of it. It seemed to irritate the heck out of it and it just kinda went down hill from there... I see you add yours to your sump. That's a great idea, it gets mixed well before flowing into the main tank, thats how I do my 90.
I used to wait until night time and you could see all the little feelers come out. Then I usually fed it some sort of meaty food. Those little feelers grabbed up all the food it could handle...
How's your alkalinity?
If it sounds like I'm grasping at straws it's because I am.  I have had a couple of corals do what yours is doing right now and it frustates me because it's hard to figure out what's going wrong when nothing has changed...
Keep in touch.
Jim
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90 Gallon glass, 135#'s of rock and 2" sand. 2-250w 20k XM metal halides. 2-95 watt actinic VHO, 4 powerheads, Coralife skimmer. Maroon Gold Striped Clown, Blue Chromis, Kole Tang, Pygmy Angel, Serpent Star, Brittle Star,Gorgonians, Mushrooms, Yellow Polyps, Turbo Snails & Blue Legged Hermits. 20 gal sump with Caulerpa, Mag 7 return pump. | 
