Well, I figured I'd bounce this extremely old post up - because I need help.
I'm DIYing a hood right now and would like to know what types of fans and where to place them BEFORE placing my orders.
So, the consensus seems to be that sucking air out of a space is preferable and really the ONLY way to do it. However, some may say that its best to have intake on one side, and exit on the other?
Now, to me that doesn't make sense - because one of the bulbs will be significantly warmer than the other one near the intake. The one near the exhaust will be warmer because it is recieving pre-heated air by the other bulb.
My plan was to encapsulate the whole hood fully (not to be anti circulation, but to create organized circulation) to the tank. With a leaning top, and 2 front doors. The back will have 2 intake holes.. driven by negative pressure, not by fans. And will have 2 fans on the side. My side fans will BOTH be blowing out. This way, each bulb has an intake and an exhaust and isn't recycling any airflow.
I have 2x 250watt halides pretty much on the way for a 55gal (pretty much the same setup as cj10488 except my hood will be slightly different.
I'm also curious as to how many fans I should get. I'll probably get 120mm fans as 80's just don't appear to be enough cooling power. I am thinking I'll get 4 of them.. 2 for the sides (blowing out) and 2 for the rear (assisting the intake of cool air).
Does this sound right to you? let me know