Quote Originally Posted by gainesvillegreen
Most fans you will find for this application do better sucking or pulling air than they do blowing or pushing.
I've heard this from several people. Does anyone know the physics behind this?

Also, I'm pretty sure 2 fans would be better than 1, especially in longer runs. If I had a bigger one and a smaller one, would it go like this?

intake>smaller fan>cool tube>carbon scrubber>bigger fan>exhaust

Or I guess, depending on how closely matched the two fans are, it might be better to just leave out the smallest one. Anyone? And where's the cut off point? At what % difference would it be best to just leave it out. If it can't keep up, it would just hinder air flow. Would the two fans need to be the same? And why are those sheep up in the trees?
Opie Yutts Reviewed by Opie Yutts on . cool tube ? extraction Hey guys n gals .. I am gonna buy a cool tube for my setup .. what fan would i need to sufficiently cool a 400w hps light ? and would the fan be pushing the hot air out of the tube or sucking it ..in other words does the fan go before or after the light .. im having a dumb moment and i reckon its extraction hence why they are called extraction fans lol i just need someone to verify lol regards :) hope someone answers :) Rating: 5