How do you prefer the directional flow of air in your canopy?

[Scissorhand]

Hi guys, I'm about to have a 4' hood built and wondering if I should mount the fans on each side both blowing air in, one in one out, or both blowing air out of the canopy? Your input is appreciated. Thank you.

[reefnetworth]

one pushing, one pulling will be the better for cooling. IME. make sure the air is directed into the room, not against the wall. good luck and REEF-ON!

[DrBDC]

Is the back of the canopy open? If so, have the fans all blow in. Any fans blowing out will corrode and need replaced.

[kneepuck]

My 4' canopy has a 4' Lexan tunnel that surrounds the MH bulbs, w/ an Icecap fan that pulls air from the outside on one end and exhausts through the other. Works well.

[AZDesertRat]

Both blowing in with exit holes up high either in back or on top is your best bet. If one is in and one is out you only have the CFM flow of one fan instead of two, you might as well only have one fan. By having them both blow in with exits on top you also take advantage of convection which helps out even more.

[Conceyted]

agreed I also have heard about corrosion due to pulling air from the canopy. have them both blowing in.

[Scissorhand]

Thanks guys. If any reefer has a canopy with these "exit holes" that they could post, I'd appreciate it. I like to have an idea of what they'd look like.

[AZDesertRat]

My canopy is totally enclosed on all 4 sides and the top. I bought a large hole saw kit from Harbor Freight Tools for about $6 that included a 4" circle which is the size fans I used. I drilled a 4" hole in each end jsut below the centerline of my lights and installed the fans inside drawing air in from each end. I then drilled matching 4" hole in the top of the canopy directly above the light reflectors so light does not hit the ceiling but air can travel up and out the top.

[coolfishy101]

Here are some pics (sorry about the extremely bad quality)

This is a circular aluminum vent about 2" in diameter, I have about 4 of these located near the top of the canopy in the back. I picked a pack of 6 up for about 3 bucks at menards.
http://reefcentral.com/gallery/data/500/63596exit_vent.JPG

Here is a cooling fan, I used a 4" 115v fan which is much more powerful, but it is quite loud. I only have one which is located in the exact middle of the canopy in the back and it is blowing in.
http://reefcentral.com/gallery/data/500/63596cooling_fan.JPG

I have had 2 12v fans, and I tried all different methods of cooling. One blowing in, one blowing out, it worked well, but the fan blowing out lasted about a month. Two blowing in worked about the same, air exited the back of the canopy, but it is against the wall and when the air blew out, half of the hot air blew down onto the glass of the aquarium heating it up. 2 fans blowing out, I didn't even try because I knew the fans were going to die pretty quickly.

The way I have now works the best and most of the hot air travels up because I was able to angle which way the air flowed with these vents.

I also recommend not having the fans blow directly on the bulbs because it may shorten the bulb life (although it is not proven, and mostly applies to MH lighting).

Hope this helps! :)

[reefdood]

I have both of mine pointing in, from the back. I added on to my existing canopy to raise it 6' taller than stock. I have a chiller and went and bought a Ranco DS, but now with the fans and additional height the temps are locked in at 79-80 solid. I haven't even plugged in the chiller or heater and with the fans I believe I won't need it under normal conditions. FWIW ;)

[Volcmreefer]

blow in from the back of the tank. The greater the fetch (wind blowing on the water) the better the evaporation (cooling) of the water will be.

[energy_crisis]

is a fan more efficient at pulling or pushing air?

[DrBDC]

The same amount of air comes out the front as goes in the back.

[Scissorhand]

Thanks guys. (coolfishy, thank you for the pictures that you posted)

I'm leaning toward having two fans blowing in from the back. Anybody having this as their current config. and encountered any problem? It should be the same and as effective as having two fans blowing in from the sides, right?

[coolfishy101]

No problem! You should be good having 2 fans blow in, and the best choice is the back too. Try to add vents on the top/upper sides too. Good Luck and Happy Reefing!