assuming that maybe its the amount of food I feed, dosing Alk and Cal along with my lighting, that's why all my corals took off. My tank is 30" deep, and the T5 lights get down to the floor very well. I am running the Current USA Pro. Its a 6ft hood with 12 - HO T5 bulbs (39W). I am running 8 - 12,000K sunwave with 4 - 03 violets. I change them every 8-9 mths. Its costly but it works great for me