MH Canopy Heat Air flow

[Medicine Man]

I have three 250 watt MH lights with two 140 watt VHO actinics all enclosed in a canopy over my 180 gallon Oceanic. I have two 4" fans installed in the canopy (One on each side). Currently I have one fan blowing into the canopy and one blowing out. Should I change it to both blowing in? My feeling is that the hot air will find its way out instead of a fan forcing it out. Sound correct? What have others done?

Also, my MH lights are facing left to right (If you are facing the tank). Is it better to have them go front to back or just leave them as is? Wiring would be much easier from back to front. What do you think? TIA!!

 

[twkenny]

Fans seem to work better if they are blowing over the water.
Front to back on the halides seems to be preferred too. Mine are end to end, because I did not have enough room to put them front to back with my actinics in there.

 

[Blown 346]

I have one fan blowing air in the canopy and the other fan blowing out, it seems to do the job very well.

 

[twkenny]

<a href=showthread.php?s=&postid=6567258#post6567258 target=_blank>Originally posted</a> by Blown 346
I have one fan blowing air in the canopy and the other fan blowing out, it seems to do the job very well.

Have you tried it both ways?

 

[Ti]

might as well try both ways

 

[Blown 346]

<a href=showthread.php?s=&postid=6567323#post6567323 target=_blank>Originally posted</a> by twkenny
Have you tried it both ways?

No I havent tried it both ways, the canopy came put together when I bought it and I left it that way, since the fans are in that position for a reason.

I think that it would work better for cooler air to be blown into the canopy, then heated up by the halides and then blown out.
Then to have no cool air enter the canopy itself, and only havhot air blown out. It doesnt seem like it would cool as efficient.

 

[Saltcity]

I have three 250W Halides and some pc's over a 125g in an enclosed canopy.

I drilled holes in the top of the canopy(at an angle to keep the light in) every few inches to let the heat out and I have three 3" holes in the back. I have two 4" fans forcing air into the canopy from the back.......seems to work fine??

 

[smoknreefrs]

<a href=showthread.php?s=&postid=6567258#post6567258 target=_blank>Originally posted</a> by Blown 346
I have one fan blowing air in the canopy and the other fan blowing out, it seems to do the job very well.

i would recommend both blowing in....you would double your cfm's....

the way you have it with one blowing in and the other blowing out, you cancel one of your fans out, so its like you are only using 1 fan...

like the saying "in one ear out the other"

 

[gobygoby]

or do like me and have 4 IC fans in the canopy for my 180. 2 on each side, both blowing in. air escapes out the back

 

[Medicine Man]

That's what I thought. It's not an "air tight" canopy so it made more sence to have both fans blowing into the canopy. Thank you for the reassurance. Always appreciated!

 

[twkenny]

Yeah, you want as much "forced" air blowing across the water.

 

[gobygoby]

<a href=showthread.php?s=&postid=6567757#post6567757 target=_blank>Originally posted</a> by Medicine Man
That's what I thought. It's not an "air tight" canopy so it made more sence to have both fans blowing into the canopy. Thank you for the reassurance. Always appreciated!

NP:thumbsup:

 

[electric130]

<a href=showthread.php?s=&postid=6567757#post6567757 target=_blank>Originally posted</a> by Medicine Man
That's what I thought. It's not an "air tight" canopy so it made more sence to have both fans blowing into the canopy. Thank you for the reassurance. Always appreciated!

yep. i had 3 blowing in at the back, bottom, across the water. i had 3-4" vent holes in the top for the air to escape. cool air comes in, across the water, then goes up taking the heat from the MH's with it.

 

[AZDesertRat]

I have one 4" on either end blowing in and 4" holes directly above the reflectors so the heat goes out the top but the light doesn't.