no, your fan does not have to oscillate. the main purpose of that fan is to simulate wind and help your stems grow nice and strong. as long as it hits all of your ladies you're fine.

as far as ventilation, you want to exchange the air in your grow room at the minimum of every five minutes. (every one or two minutes is ideal, i think.)

to find cubic feet you use l x w x h. so you would have 2 x 4 x 4 or (2 x 4) x 4= 32 cubic feet. so your 225 CFM fan is plenty of sufficient for your needs.

the intake hole is another thing. you want to create a negative pressure in your cab. you do this by exhausting more air than you can take in. this negative pressure draws in fresh, 02 rich, cool air.

i guess this is normally done with smaller intakes than exhausts. i've read all kind of opinions on the subject. you might have to play around with this.

good growing!


-shake