Thanks for replying, I have a 46 gallon, my light is a 36 in with 1 actinic and 1 10K bulb, I think 196w. the bulbs I replaced about 3 months ago. My tests have all been good and I use RO water. I have a yellow tang, sailfin tang, scopas, blue hippo, spotted goby, hawk fish, Dotyback, and a pair...