Question about fans!

Ok, so I will be growing in a tent that is 4'x4'x6'. I am going to buy a 6" Vortex Inline fan (450CFM) to use at the top of my tent. It will be sucking air through my carbon filter, then through my cool tube on my lights, and finally out of my tent. My question is what kind of fan would be best to use for blowing air into my grow tent? I obviously don't need something as powerful, so I'm hoping it won't be too expensive.

Also, can someone please clear up the difference between fans that suck, and fans that blow? I'm pretty sure inline fans suck air because they are typically attached to carbon filters, but i'm not really sure which kind of fans blow. Or, could I just buy another inline fan and use the other side, so air would be being sucked in from the outside of my tent? Thanks guys!

I would bet you`ll get negative pressure in your tent without an intake fan.

I think fans can suck or blow. Just more efficient sucking. hahaha

http://htgsupply.com/Product-6in-Inline-Duct-Fan I use this with my light hood. I pull air from outside the tent, through the tube, and out the tent. Never has smelly air in it because it is on a closed loop. Then I have my more powerful inline fan pulling air from the top of the room through the carbon filter and out the attic. (I have a larger then necessary fan, that I put on a dimmer to slow the outtake...To hopefully preserve the motor, but more importantly, it makes it much quitter) For intake, put a couple vents lower in the room for passive air intake. Hope this helps