Hmmm...I run 10 hours max (420nm for 2 hours, 14000K for 6 hours and 420nm for 2hours. I have the moon lights run a few hours before and after). I would think anything more than that could be advantageous for algae growth. My LFS recommends 8 hours and I have to believe them since their coral systems and show tanks are absolutey insane. However, if it ain't broke don't fix it. On another note since I changed to this lighting scheme a year ago (from 12 hours and halides on the whole time) my coral bandeds haven't had babies. They cranked them out every 3 months for 2 years. Maybe the male has ED.