Effects of extended light cycle on corals?

[fredro]

What kind of negative effects can too long of a light cycle have on corals? My mushrooms are slowly and slightly shrinking and leaking the photosynthetic stuff from their mouths. Also have an open brain thats spitting out very small amounts. Ive checked my water chemistry so many times and find nothing that seems out of the ordinary besides a slightly lower alk than I'd like at 2.75 mel/q.
Any thoughts?

 

[KathyC]

Too much light can kills corals.

What is your lighting cycle?

 

[fredro]

Day start: 8:45a
Night start: 10:15p

but it ramps up and down pretty slowly.