how much space from a MH in a canopy

[m88a2]

Im thinking of building a canopy for a 24x24x12 shallow reef housing a MH fixture and maybe some hydras. How far away should i keep the MH from the hydras so it doesnt do heat damage, should i add fans or head shielding? what if i vented the top of the canopy or left the top totally open? also should I have a standoff from the MH fixture and the wood? any chance of it catching fire?

 

[JPG@CFI]

A nice 150W MH would be what I'd use. No need for
a 250W+. I use a double ended 150 on
a similar size tank, and the fixture
s fully
enclosed. I did use a spacer to mount the fixture to my
wood
canopy. The
canopy is vented with a fan that exhausts hot air out. The canopy height is 12" above the water and the bulb is 8" above the water. Good luck, J

 

[m88a2]

awsome, thnx for the reply