Canopy Fans? Blow in, out, or both?

[Augusta99]

I'm mounting 2 canopy fans tonight. Should they both be blowing air in, out, or one in and one out. Fan are converted PC fans, are 2 enough to provide cooling?

I'm running a 90 gal mixed reef with 6 t-5, and looking to save a little electricity verses using only my chiller to keep things cool.

What about placing fans in the sump area too?

[grimreefer01]

in on one side, out on the other

[grimreefer01]

oh, missed the second part.. not sure if 2 fans will be enough, it should be though, depending on size and air volume pushed by the fans..

for example, a hamilton tech 2 x 250w HQI + 2 x 110w VHO setup uses just 2 fans from the factory, and keeps it plenty cool..

[Inked414]

I'd say it would depend on if your canopy had an open back or not. If it is open, you can have them both blowing in. But if it is a closed back then you'd want one blowing in and the other out for air circulation.

[Augusta99]

The canopy is open back.

[billdogg]

because it is open in the back, i would have both blowing in - they will also last longer - if you have one blowing humid salt air out, it will corrode fairly quickly

[Augusta99]

Thanks for the info everyone! Tonight I will install the canopy fans to push air into the canopy, and let the open back handle the air flow out. I plan to also install some fans around my sump to get heat out of the area below the tank too.

[reefworm]

agree w/billidog. the other advantages are more surface agitation for better water/gas exchange and added evaporation - the latter allows more cooling and greater capacity for kalk drip/top off to replenish Ca++ anb buffering