How High

[blkhawk10]

I've been flirting with the idea of moving my metal halide lower toward the tank and I was wondering what is a good height to have a 150 watt above a 29 gallon? Right now I have the light at 8" above the water...I don't have a par meter, but assume the light can be at a decent height above the tank with good light spread and still grow corals.

 

[OurReef]

I run my 400s around there. That's to the bulb not the fixture correct?

 

[Dumnorix]

You can put them closer than that. Just move your corals down and out to the sides at first if you think they are going to get burned, and move them up gradually to acclimate them to the light. I have seen 12 inch deep frag systems where the light was 2 inches from the water.

 

[blkhawk10]

No that's to the fixture to the light is probably 11".

 

[Ike]

If you're 8" above there's no real good reason to move it down... Also, the height a fixture should be above the tank is greatly dependant on the reflector and it's yusually best to go by the manufacturers suggestion if they have one.

 

[OurReef]

Just measured mine 9.5" from water to bulb.

 

[Trex]

Are you happy with the light spread?
Are you happy with the coral growth (( granted there are other factors ))
Are you happy with the amount of light spill into the room?
Are you happy with the temp of your tank?

The answers to those questions will be a huge factor in the height of your fixture - every case is going to be different.