Metal halide height above tank

[UCF]

How many inches should my 2 x 150 halide + 2 24 W actinics be above the glass lids of the tank?

Currently I have it 6 inches above the tank. Just wanted to see if that was too close or not close enough. I Will be keeping all types or corals and some clams when the tank matures. Thanks

 

[orionsmamma]

I think most people will say at least 8 inches above the water surface for halides. This is really a heat issue...Halides put off a bit of heat, and the closer they are to the water surface, the more heat the tank gets. My halides are 12 inches off the water surface, and I have seen a few tanks with them 24 inches above water surface.

 

[bertoni]

If your tank is not overheating, 6" is fine, IMO. If it is, I'd try fans before moving the fixture. Moving the light up will reduce lighting intensity in the tank, which can be either bad or good, depending on how much light your future corals will want.

 

[UCF]

Thanks guys. It actually isnt that hot so I will leave them be for the short term. If I see an increase in temp I will move them up slowly until a happy medium is reached.