DIY carbon filter, will this setup work?

Hi,

I'm going to buil one of these diy carbon filters: Easy to Build DIY Carbon Filter - Marijuana Growing

My grow room is 60x120cm, 2 meters tall, I will have one intake fan blowing inside the closet and one fan going outside, to the carbon filter. The exhaust fan blows somewhere between 15 to 25 cubic foot per minute.
My question is, will the exhaust be good enough to remove the smell of fresh buds? There will be seven lowryder no.2's, so the smell would be pretty strong.

Or is there no difference, as the fan would be constantly blowing the air outside, though not very strongly. Or would more powerful fan be necessary?

Also, any recommendations on how long I should build the filter? I was planning something like 30-40 centimeters, 12-16 inches.

Thanks:thumbsup: