hieght of halides

[200 gallon reef]

I was wondering if anyone had an idea of how high off the surface of the water I should hang my 3 250 watt halide fixture. All 3 bulbs are 12 k. I do not have anything in the tank that needs a significant amount of light. It is a 200 gallon tank:

Thanks

 

[Gti_Leo]

atleast 8 inches above, and get a few clip on fans to blow across the surface to help keep things cool