What size fan/filter combo do i need?

I have a 12x6x7 room with 20 pots, what size (4",6",8"...) fan and filter combo do I need and what should the CFM rating of the fan be? I plan on adding a hepa filter to the carbon filter/fan combo.

Also what is the difference between the original Can Filter and the 38 Special Can Filter?

figure out your cubic feet of the room first

dgk4life said:

figure out your cubic feet of the room first

Click to expand...

504 cubic ft=6'x12'x7'

now when shopping for fans and filters u jsut look for a fan and a filter that have a higher cfm

i would go with a profilter 75 reversible carbon filter... https://ssl.cgicafe.com/clients/hmoonhydro.com/profilter.html
with a 8 inch vortex fan https://ssl.cgicafe.com/clients/hmoonhydro.com/control_vortex.html

dgk4life said:

now when shopping for fans and filters u jsut look for a fan and a filter that have a higher cfm

Click to expand...

What do you mean by that? The filter's CFM rating has to be higher than the fan's CFM?

I have a 6" vortex fan for my lights and an 8" on full blast all the time would be overkill and loud as hell. I was thinking a 4" or 6" at most

yeah its a good ration because if uyour fans cfm is higher then your filter then u arent really cleaning all the air.. so by pullin less air through your filter then its rated for you ensure proper cleaning