cooling off metal halide bulbs?

[tableforglasses]

Well I just got my canopy put on and everything installed over my 110 gal tank. The bulbs sit around 12'' from the water. I am currently running a 400 watt Metal Halide w/2 48'' actinic bulbs. Already the hood is getting really hot. I have a fan installed at the base of the halide bulb, and I am trying to figure the best way to cool this baby off. My hood is fully enclosed. I have looked at other posts, I noticed broomers fans were at the top of the hood inset. Is this the best idea, does anyone have suggestions on how to go about cooling these things down, and how much should I be concerned about the heat. Thanks for any info guys
Sean

 

[broomer5]

Sean,
You don't need to worry about cooling the MH lamps.
They're going to run hot no matter what you do.
The trick is to remove the hot air out of the enclosed hood, by drawing in cooler room temperature air, and exhausting the hot air OUT.
Mount some fans in the hood and allow for some venting near the bottom of the hood/water surface.
Draw cooler air in
Blow warmer air out

 

[tableforglasses]

broomer with your setup I noticed on some pics that you had two fans up top is one and intake of air and the other an outake of air, also how did you get the fans in, I was thinking about using my jigsaw and cutting out a box, but not sure how I would mount them like that.
thanks for your help
sean

 

[reeflooker]

Sean,
Do you have the water in the tank yet. I am curious about your water temp. Also, how many fans are you going to use. Are you conserned about noise?
Reeflooker

 

[tableforglasses]

right now the noise isn't too bad. no worse than any other piece of equipment, I got one fan from radio shack and I am thinking about adding another one, so far I cannot tell that it will cause a rise in temp. But the air inside the canopy is very steamy. I imagine it will only be a matter of time before it gets really steamy and the water heats up, that is why I am trying to get some of the hot air out. I hope it works
sean

 

[tableforglasses]

broomer (or anyone w/knowledge)
will it work just as well to drill in the top backside of the canopy, it would be less noticeable there than on the top, will I get the same affect or should I def. drill in the top?
thanks sean

 

[broomer5]

I think much of "our" ventilation design on our canopies is a personal choice.
I like fans blowing out.
Pulling in cooler air from the bottom.
Top or back/top would be best IMO.
Ventilation near the bottom of the canopy in the rear is how I chose to allow cooler room temp air to be "drawn" in.
This cooler air then moves up, past the hot bulbs, moves heat up and it is forced OUT the top.
Heat rises - why not take advantage of this natural occurance.
jigsaw works great for round cutouts.