Ventilation Fan Question

My grow room is 2' wide 3' long 6' high closet grow room it is enclosed and self made out of foam board reflective insulation.. i ordered a 250 CFM 6'' inline duct fan and also a 80 CFM 4'' from Htgsupply.com heres the link for what i ordered- http://www.htgsupply.com/viewproduct.asp?productID=46447 and other one is http://www.htgsupply.com/viewproduct.asp?productID=46434 anyways i have a 400 watt HPS light and i am going to put the 250 CFM for exhaust in the celing and the 80 CFM on the bottoom for intake.. i think its good that way because its good to get the heat out instead of recirculating it. But the difference in CFM for the fans is big.. im gonna be sucking more air out than im pulling in. Will this create a vacuum, or will it mess anything up? If so what can i do to fix that

use both of the fans as exhaust and have 1 big passive intake hole.
you dont need to use a fan to push air in, it will get pulled in by the exhaust.

Its good to have an exhaust pulling air out, as well as a circulating fan to move the air to the corners of the room. Intake is automatic, it is very tricky to make a grow room air tight, though it can have its benefits...

you will have a vacuum but thats not exactly a bad thing. Does your light have vents on it? I would leave the 250 where you have it and hook the 80 to exhaust just the light with a separate intake vent hooked up to it for your light 2. this way the light stays cool which is what is making the heat to begin with. Or if your light doesnt have vents just mess around a bit with the light on and see what gives you the lowest temps in the room.

you may have trouble keepin a 400 cool in there with that setup. I had a 2x3x5 until recently and i ran a 400. I needed a 440cfm exhaust and another 440 on the lights

are these fans even the right ones to be using? So let me get this right.. i dont even need an intae fan? just a vent in the wall?

those fans are booster fans. they dont move alot of air.
have those fans as 2 seperate exhausts, and then have a large hole for the intake.
read these topics on ventilation.
https://www.rollitup.org/view.php?pg=faq&cmd=category&id=67