How High Should I Hang Lights

[ChrisK]

I have two 250 watt 10K MH lights and two 110 watt VHO's in an enclosed fixture. How high should I hang it above the water surface? My tank is 75 gallons and the depth is 18". Currently it hangs 10" fron the surface but I was wondering if I lowered it if it would increase the intensity and therefore benefit my SPS more? Any Ideas?

Thanks

[jojo22]

Should be better at about 6-8 inches off the water, as long as you get even light coverage (no dark spots on the sides or in between the lights) you will be fine.

[melev]

Metal Halides should be 9 to 12" off the water. This usually covers 24" x 24" per bulb. VHO bulbs should be 4" off the water, but set up so that water doesn't splash them and cause issues. Here's a picture of how mine are suspended.

[pro2k]

Geez melev! Do you have to put sunglasses on to even see the tank?

[graphixx]

I would go at least a foot. that way you have some room to get in there and your not cooking the stock.