View Full Version : how high should my halide be?
Eric B 125
03/03/2011, 07:43 PM
i have a 3 bulb MH fixture, though my tank has a center cross brace. i'm going to build a canopy with an open top to put the fixture in. how high should i plan on putting the fixture above the frame?
coralfish
03/03/2011, 07:49 PM
8 - 12 inches, what size bulb and on what size tank?
Eric B 125
03/03/2011, 08:02 PM
3x 250watt, 125 gal
coralfish
03/03/2011, 10:06 PM
yes, 8-12 inches..12 inches if heat is an issue, 10 is a good average
Eric B 125
03/04/2011, 09:27 AM
cool, thanks. i just worried about the center brace melting with a halide over it . i'll put a fan in the canopy to help with heat.
Angler7
03/04/2011, 09:31 AM
does it necessarily have to be 10 inches?
Eric B 125
03/04/2011, 10:13 AM
no, at least i dont think so. the minimum height, in my case (from what i understand) would be roughly 10 inches. i could go higher, since air doesnt diffuse the light like water does, and wouldnt lose (much) PAR. i would rather not go much higher because i dont really like the look of high-profile canopy's. my issue is just a matter of the center brace and heat.
gweston
03/04/2011, 10:14 AM
I am finishing up a stand and canopy for a 125 long. My canopy is approximately 73.5"x19.5"x12". My 3x halide reflectors are going to be mounted about 2-3" below the canopy top. So this will put the reflectors and bulbs between 10-11" from the surface of the water I suspect.. give or take.
The supplemental T5's will be mounted adjacent to the halides, but a bit lower. The T5 reflector will end up at the same height as the bottom of the halide reflector. The T5 bulbs actually hang down maybe an inch or so below the reflector.
I then have 2x 80mm fans on each side of the canopy (right and left sides), that will blow inward. The fans are to be positioned close to the ends of the T5's, but there is some overlap. It will blow air across the T5's and the halides.
The rear of the canopy is open. Not sure if I want to close it up. I'd rather leave it open for heat to escape.
Even though I have the measurement details worked out. I am still wrestling with what to mount the retro fixtures to. I have some 1x2'x and 1x4's I could cut to size. But I am looking at some aluminum c-channel stock. I am leaning towards wood, as I am way over budget and I have the wood on hand.
Eric B 125
03/04/2011, 12:06 PM
gweston: does your 125 have a center cross brace, or two cross braces on the top trim?
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