Distance From Water for MH Lights

[izib]

Im redesigning my canopy and am woundering how much distance I should have between the bottom of my MH and the top of the water. Ive got a 90gal tank with 2 250watt MHs with parabolic (sp) reflectors. Right now they are only about 5.5", I was thinking thats a bit close...

 

[broreefr]

I just built a new hood for mine and originally they were 10 inches away but in the new hood I moved them to about where you are now 5 inches. I see a big difference in light in the tank and am much happier with them closer ~ I do have a piece of tempered glass between the bulbs and the water, I would think as long as you take that precaution, you should be fine