Side by Side fans?

[plasticine]

I only have limited space in my canopy where I can only fit 2 - 2.5" fans side by side. I was wondering what peoples thoughts are about air flow direction.
a. All air blowing into the canopy
b. All air blowing out of the canopy
c. 1 in and 1 out.
Given that the back of the canopy is open, I figure that there wouldn't be much air being pulled out of the canopy so I am leaning towards a. and blowing into the canopy. Thoughts?

 

[mpls man]

personally i'd go with c , thats the way i have my fans going , although i have 2 - 4 " fans on my canopy, but the temp never goes above 80* for the tank, i think 1 in and 1 out cools the air in the canopy faster then all air going in because the hot air dosen't have any way to escape.

 

[6stokes]

What are you trying to cool? I'll assume it's the water. That being the case they need to blow on the surface of the water. Anything else only cools the ambient air which only very minimally heats the water. It's the penetrating light that significantly heats the water. It's called radiant heat.
Your idea of "a" is the best cooling in your situation.

 

[6stokes]

BTW, blowing all air into the canopy doesn't trap the air as suggested in the other post. If it did it would blow the canopy off the tank. All the air is escaping out the back. So, it's doing two things, cooling the water and removing the ambient hot air from the lights.

 

[nd30male]

Here is a few pics of the hood i built for my 46 bowfront i vented the side close to the bottom of the hood so it pulls in cool air across the top of my water keeping it cool then i have 4-2.5 fans sucking the air out of the top of the tank making it easier since heat rises. Im running 192 PC and 250MH and i can keep my water as cool as i want it. my heater kicks in the middle of the day i only have .4 degree temp change in my tank and im not using a chiller.

 

[plasticine]

The fans would be blowing over the bulbs and a bit over the glass top. The bulbs are about 2" from the surface of the water but I have put a glass top there to protect them from any splashing and such, but they are running hot and wanted to cool them off a bit.
As far as blowing 1 in and 1 out, any thoughts on which is closer to the back and which to the front. Just a quick thought as it might make a difference in air flow.

 

[nd30male]

If you think about what happens to a car in the summer months? The sun shines the windshield magnifies the rays and your car heats up your probly better off removing the glass top and raising your lights. As far as running your fans across the bulb i dont think that would help much might drop the temp of the bulb a bit but the main reasons for your fans is to move the hot air away from your water and out of your canopy.

 

[6stokes]

I totally agree.

 

[plasticine]

ok, so aside from building a new canopy I cannot raise the bulbs any higher.
How would this be any different than the pre-built setups like aqualight or similar? I have seen setup where the lights were on pegs and they still had a glass top. difference is that these have fans built in.
What I will do is put the fans in a try different configs. If I have to I will try to add 2 fans in the lid and suck the air out the top also.

 

[nd30male]

Well in the store baught lighting i had the same problem with over heating cuz of the glass not only doese the glass magnifie it allso holds the heat in not allowing it to exscape. But none of that matters in your case if you dont want to build a new canopy i guess in you situation with the open back i would mount them in the top blowing up. this will suck the heat out of the top bringing in fresh cooler air across you glass and bulb sucking the heat away form your water.