How high to place fixture above tank?

[Jambro]

I currently have a 125 gal tank and have a total of 760 watts...2 250's and the rest atinics. It is placed 8 inches off the top. Halides are on 6 hours and atinics on 8. LPS are doing great, small SPS frags, half way up, seem to brown out. Water parameters are good. Should light be higher? Anyone with a similar setup and how high is your light?
Thanks

[docs911]

When I built my canopy, I was told to place them 6 to 8 inches above the water. Mine is set at 9 inches

[reeftank21]

You might try a poll to get more response. I have 250's about 9 inches off the water and am considering moving up. I see many people who put lights much higher. 18" to 24" . Most tanks that I see with the lights much higher seem to be doing better than mine.

[amt68]

I have the same lighting period as you. My tank is only 13" deep. I have 2 250w reeflux 10K on coralvue elec ballasts with the bulbs about 14" from water surface. 2 4ft VHO actinics on icecaps. I've had the same problem with brown corals. Recently I moved my lights up about two inches to the above mentioned hight, and my corals seem to be improving, I think I may raise them another inch at the end of the month, or reduce MH to 5 hrs.