height of lights?

[fishfan09]

How high should I hang 2x 250 watt halides ove a 75 gallon? I am building a canopy and was plannin on 8" to 10" is that to low?

 

[columbusreef]

I have mine 6" above the water

 

[fishfan09]

How many fans are you running?

 

[Reefdiver72]

it just depends on fans is it in a closed canopy or what?

 

[fishfan09]

Open back and I was going to use 1x 4" fan is that enough?

 

[hllywd]

Maybe... Mine are 8" off the water and the canopy is enclosed. I have 2x 120mm fans to clear the heat out of the canopy. Didn't realize I had as much of a problem with heat as I do until I started looking at the graph... I have more of a temp swing than I'd like, but once my LEDs come in and I get the fixtures built I shouldn't have to worry about it! I'm sure your open back will help, but you may still have an issue.
Tim