How hot would these lights get?

swreefer · 11-01-2001, 01:08 PM

I would like to attach the 175W MH retros (the ones on the 2x2 reflectors) into the canopy on my tank. They would be about 4 inches from the water. How much heat would these things give off since they would be just the lights? Tha ballast would be placed in the stand. The canopy is completely open in the back so the heat could get out but there are no fans. Are fans a must have with MH?

reefguy · 11-01-2001, 02:04 PM

i have 2-175W metal halide bulbs and they give off a significant amount of heat, but not anything that couldn't be managed with a couple of small cooling fans. i have my fans wired separately from the metal halides. the fans come on when the actinics do (2 hours before the halides) and go off two hours after the halides do (along with the actinics). i have been able to maintain a tank temperature of 78-80 F even with a room temperature as high as 76-77 F. i would definitely recommend remote locating the ballasts as they also produce a significant amount of heat (they get to around 120 F or so). hope this helps...