Dee-ive been using thoses 15ks since i set the tank up.the only thing is that i supplement them with 2-39w and 2-24w t5's.
another thing is that ive been dosing brightwells low nuterient system,AA,BF,MB7 and KC.
ive also been feeding REEFUEL from coraldynamics.com
jeremy at B&B had some phoenix 150w,and i would have to say they are really nice looking,realy blue,when im ready to change out my bulbs i might go with either those or XM 20k.