400w Meatl Halide

JMalone81

New member
How far should 400 watt metal halide reflectors be away from the water?They are Lumenarc reflectors.Also how do I keep from shocking the coral?I am going from t5 to 400 watt MH.
 
I think the general consensus is that the bulb needs to be something around 6-8 inches above the water. This is because of IR heating and to avoiding splashing the fixture.

To avoid over-illuminating your corals, you might need to move it further--depends. Start conservative and slowly bring them closer.
 
I put my 400's about 13" above the water line. Just monitor the water temperature. I also have an intake and exhaust fan in my canopy blowing on the water surface as well. If temperature is high you might want to add fans or place higher.
 
When I had 400's I ran them 5" above the water.

I just switched to an ATI Powermodule (T-5) and it was a shock to the corals.
 
Somewhere between 5" and 13" above the water. I think most place their MH lamps about 8 or 9 inches above the water.
 
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