canopy question for 250W MH's

[32flavors]

I am building a canopy for my halides, and I would like some input on the best exact distance from surface to bulb for 250W mogal MH retro fit?

There will be 2 bulbs on a 75 gallon tank and 1 on a 65 gal, if this matters.

Also, do I need a heat buffer space between the retro fit and the top of the canopy?

And, finally, I have Silenx fans I will be using--is it best to install them higher in the canopy near the bulbs or slightly lower, or does it make much of a difference?

Thanks all!!

Cheree

[snulma1]

I think that putting the bulb approx 5-8" will give you enough space to not have to worry about the occasional splash. and still provide ample light.

And yes, you should provide some space for air circulation between your reflectors and your canopy and reflectors.

As for your ventilation, there are different opinions on this. I personally liked drilling a few holes on the top of my canopy and running 2 fans on both ends, one blowing in, the other blowing out.

[xtm]

I have 4x 4" holes on the back of the canopy + 3x 4" fans... also in the back.. the fans are all PULLING air out of the canopy. I built it like this for aesthetic purpose since I don't want the light to leak out on the sides and on top. Works great.