Fan size for grow room

What size inline blower fan/ducting should I have for a closet grow with the dimensions of 3.5'x7.25'x9'?

I'm thinking 6" with 6" ducting and 6" carbon filter.

not necessarily mines a 3" in 4" out, check my vid YOUTUBE mrbigbud75

depends on lights aswell and heat build up

I will be using a 1000w air cooled HPS by the way.

yeah 6" deffo & get a decent reflector or angle one properly to suit the room dimensions. 30+ plantswith tha easy