What size fan do i need??

I am setting up my new room, It's the biggest i've done so far. I plan on having a 36 pot flood and drain system with 6 pots under each 600 watt light. I have just bought the air cooled supanova hoods i'm going to use and wondered what size fan i will need to cool the bulbs???
I plan on running ducting from the boxing in over the window, through the hoods, out the fan and venting through a chimney stack. Also i am running co2 in the room rather than pulling in outside air. And a venting fan connected to a big carbon filter.
Plus just bought an automatic doser and ph'r so hopefully this will make things much easier
Any advise would be very appreciated

how big is the room and how many lights are gonna be cooled mate, my 8" inline will cool 6x600w any more lights and i'd have to up the size of the fan i'm only running the 2 lights but these are the manufactures guidlines

as a rule of thumb you need to change the air every 2 minuits soooo

If your room is 5x10x8= 400 sq. feet

you need a fan that moves 230 cfpm.

Plus fan for cool tubes.

peace

I'm running 6 x 600 watt. Thought an 8" would be ok. Gonna get an 8" Airforce fan.
I've got a 10" airforce with 10" carbon filter for changing room air, It connects to my co2 computer and only vents when needed. Its a cool peice of kit!! Just input room size and desired co2 levels and it sorts it out