Thanks for the reply. My post above wasn't very specific. My concerns are with premature failures where the lamp burns out & typically leaves a dark spot on the glass about 1" from the end (sometimes burning all the way through the glass). I posted elsewhere about this with my power compacts. I had switched all of my tanks over to these lights and while I was/am happy w/ the light output & color - the fact that I randomly get these burnouts is a pain. It always seems to happen when I go away for a weekend or a week. I don't know if I ever had this happen w/ T-8's.