Cooling fan in my DIY wood canopy

[exmt]

Hello out there, I'm creating a DIY wood canopy for my 29 gal FOWLR tank.

It'll be appox 32 in wide, 20 in deep, and 4 in high. I'm mounting in 2 shop light fixtures in the canopy, each with two T12 bulbs rated at 20 watts each. So that'll be 4 tubes, with 80 watts of lighting total.

Now cramming in 4 light tubes in such a small space..not to mention 2 moonlight tubes could create a whole lotta heat. I'm wondering if I actually need a cooling fan, because there are a lot of bulbs, and no vents on the top..only a bit of space at the back.

I'm planning to use this PC cooling fan:
http://xoxide.com/80vanstealfa.html
Its the Vantec Stealth..has anyone had experiece with this one? It seems very quiet.

It says it has a 3 pin/ 4 pin adapter, but the DC tranformer I'm using has only 2 wires, Positive(red), and Negative(black).

What would the third/fourth wire do? Is it a grounding or something? Would the fan run fine if I hooked up only the red and black wires together, or would I need to somehow use the third one?

Thanks for the help, I have little knowledge of electronics and their workings...

 

[exmt]

Bump for morning shift.....posted this late at night.

Please help me out here..Do these:http://www.lowes.com/lowes/lkn?action=productDetail&productId=163705-337-0401030003&lpage=none
Shop light fixtures have an electronic or magnetic ballast?

It says it has a trigger start ballast, but what does that mean? Is it electronic or magnetic?

Thanks for the input.

 

[Fast Fred]

I'm not at all familiar with that fan. No idea what the extra wire(s) do. I've used Radio Shack fans in the past with no problems. They only have Red and Black wires on them. Just be sure to have the fan blowing into the canopy, and have someplace for the air to escape.

That fixture is likely to have a magnetic ballast. A laymen could tell by the weight. a magnetic ballasted fixture weighs twice as much as an electronicly ballasted fixture.

 

[navyav8tr]

I was actually looking at some fans at Comp USA the other day and there was the red and black wire but also a yellow one. I am curious too as to what these extra wires are for.

 

[swellsearcher]

Typically on a computer fan the 3rd wire is for a speed controler. The stealoth fan is a great fan for this purpose.... it is very quite and moves alot of air. On this model the extra wire is for what I said. If you do not connect it the fan will run at max spped (default)

 

[Phyxius]

swellsearcher has it right. The 3rd wire isnt needed in the canopy installation. Your computer uses them to monitor speed of the fans if set up for it. Just either tape it off or cut it off. I nip mine off close to the connector and put a small piece of heat shrink tubing on it.
Those fans are pretty quite and should work good for the 29 canopy.

 

[exmt]

Thanks guys!, now I understand this.

So the fan has to blow into the 29 canopy, and the hot air will exit through the vents? Or is it the other way around?

The transformer i'm using is rated at 12v 20watts, and the fan is rated at 12v 1.2watts. Will the total unit(both of them) use 20 watts or the original rated 1.2 watts?

Would a sheet of plexiglas be good for keeping water off the bulbs?

 

[bassnman11]

If you measure the height of a shop fixture, I think you will find it 3 to 4 inches with the bulb mounted. I would make the canopy at least 6 inches high to get the bulbs off of the water a little. You can mount your fan in one end of the canopy blowing in or on the back so the air goes in one side and out the other.

 

[Fast Fred]

Volts stay the same, but you add watts together. And as long as the total doesn't exceed the total output wattage of the transformer, you're OK. (Running transformers at 80% capacity or less is always better.)