I think its the lights.. the corals that need more light are the ones dying first.
I havent changed my light bulbs for over a year, so its most likely the lights! Ive also done massive water changes since the corals have been dying and water arameters are perfect.
Only other thing I can think of is the lights....
The lights are not completely out.. just not giving the right wavelength for the corals to survive I guess.
BULBS STILL STUCK IN MONTREAL! GRRRRRRRRRRRRRR......