Canopy Fans

[smelleybrad]

Which is better, do I want them to blow the air out or suck it in?

[JimD]

You want them both blowing in to evaporate water, thats how they cool the tank...

[eric]

I would do blowing air in. My reasoning is first, I'm a little less likely to build up salt as fast on the fan by pulling it through. Also, I figure that blowing air directly on a water surface allows me to know that there's the contact with the cooler drier air. If you're sucking air, then it's more difficult to know exactly where your source of fresh air is coming from and the path it takes. Lastly, if I were to suck air, I'd be throwing the moist air straight at drywall.

[smelleybrad]

Thanks, I'm sure somebody has already told me the answer before but I seem to forget things sometime. Maybe it has something to do with Iraq, a car, 500lbs of explosives. LOL

Once again thanks, Brad

[Reef69]

Brad, I have 2 fans blowing in my canopy, they work awesome, I have 2 x 85 CFM fans, they do a really good job.

[GaryP]

Brad,

You're better off getting high CFM fans although they are a bit noisier. You can always put them on a timer to go on and off with your lights. The times of the year I have the most problems is the fall & spring when the windows are open and the humidity int he house is highher. That's when you want more air moving because evaporation, and thus cooling, are lower. I have 2 100 CFM fans on a timer with my lights and another two that are sort of backups when I have a cooling problem as I mentioned earlier. Of course it just depends on your lighting. I have 2 X 250 watt MH and 2 X 160 watt VHO on my 125. My 75 just has one fairly low CFM fan for the 4 X 110 watt VHOs on it.

[smelleybrad]

GaryP, I wish I would have read your post before I left to Radio Shack. I just bought one for now to see how it would work. Its about 3 1/2 inches, 3100RPM, 32CFM, 130mA, 115VAC, 60Hz. I have no idea what all that means but that little thing is really putting out. I will have to go get another one now.

[GaryP]

Just see how it does and then add another one if you need to. What works for me may be huge overkill for you. Just monitor your temp for a while with the AC on, as well as the windows open. The key thing, I believe, is not the temp in your house, but rather the humidity. An aquarium operates like a giant evaporative cooler. It gives up huge amounts of heat by evaporation. The purpose of the fan is to provide lower humidity air to increase evaporation.

[eric]

The key thing, I believe, is not the temp in your house, but rather the humidity. An aquarium operates like a giant evaporative cooler. It gives up huge amounts of heat by evaporation. The purpose of the fan is to provide lower humidity air to increase evaporation.

That's key, it's not the temperature of the house, but the wetbulb ('dew point' is close enough - but who measures either inside) compared to the air temp. Then again keeping the house cool by way of the AC is also going to be drying out the air.

Lick you finger and blow on it. Your finger gets cool because you're removing the heat in the water.

[Richard]

Blowing air out doesn't do much as others have said. Have them blowing air in and vent the top of your canopy so the heat can escape.

[z28pwr]

I always had push fans and a pull fans to move as much air through the canopy as I could. I've used Orion fans for some time now and have had good luck with them, try to get the highest CFM fan possible with the lowest decibels (DB). If I recall correctly Orion had around 50 CFM with 25 DB fans.

Remember every three decibels is TWICE as loud so don't think that going from a 25 DB fan to a 30 isn't going to be much louder and last thing you want is a helipcopter in your canopy.

[Reef69]

The 85 CFM's i have are very quiet, got them at Radio Shack...

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=273-238

[bprewit]

fans or vents on the top of your canopy will help as well. Heat rises of course and if there are no fans or vents or other means of escape the heat will build up inside the hood being circulated around by the fans blowing in. Just my thoughts and experience. I mounted two small fans on top of my hood that pull air from inside the hood and vent it out through the top as well as two fans blowing in across the top of the water.