Biggest mistake is too much intensity. I followed similar advise as above and it cooked my coral at 60 %. On a 210g tank 30 inches deep....These lights are strong. At 8" high like mine, I'm running 6% B and 1 % W. And I'm getting tons of growth. At 60 I had no growth at all, and a slow decline over the years. People make the same mistake with kessels and complain about no growth, lights were way to bright.
