Have you changed the light recently [the last two months]? I think 8 bulb t5 on that setup is way too much light for those corals. All you listed are only needing of pretty low [intensity] light... I would cut back the photo-period (Timing of lights) 1/hour a week and see if it doesn't get better. Even if they need particular parts of the light spectrum to live - You can kill corals with even too much [intensity] of the same light [spectrum in nanometers]... For example - while corals do need some "actinic" light to survive, it is possible to over-saturate and kill corals with way too many Actinic bulbs. Speaking of, what bulbs you runnin? <-------- just curious; either way I would scale back the photo period and see if that helps.