Carbon filter set up

[Canadianclstgrower]

Hey guys I’m a pretty experienced grower but am pretty more to indoor set ups I have a 190 cfm fan and carbon filter coming for my 2x3x8 closet I plan on running the fan at about half my question is what will be better for me to use like a 6” passive Intake or could I use like a 3-3-3/8” with a small USB fan to help draw in new air I just want to make sure the girls have lost of airflow while still keeping a bit of neg pressure I added pics of my current (very bad) ventilation system that idk I guess it brings in fresh air but I plan on ducting from the top and out the door I will add a 4” vent so it’s not just a hole in the door like it is now just would love advice on setting this up right

 

[Canadianclstgrower]

Pretty new to indoor set ups *^

 

[Dwight Monk]

Passive seems to work fine for me in my shed, my boxes had both intake and exhaust. I just use that carbon pre-filter stuff you can buy by the roll and cut to fit, helps filter out anything big thru intake and helps keep light from coming in thru the hole/vent.

 

[Canadianclstgrower]

Okay awsome thank you very much

 

[Canadianclstgrower]

What size would you say for a 4 inch 190 cfm with a filter I’ll probably dial the fan down some too

 

[Dwight Monk]

Not sure on the cfm of my 6" filter, but in my shed I cut a hole in door slightly smaller than the furnace plate I bought (and put the carbon filter stuff between plate and door (it's 10x10" or so hole), as the air has to come from somewhere that it sucks out not sure you can affect that much if passive air as it would just bring it in faster I would think. But I would go with at least the same size as your outlet or slightly bigger, unless you forcing air in then just get the cfm of inlet and outlet close to each other (though again at least same size hole).

 

[Canadianclstgrower]

Not sure on the cfm of my 6" filter, but in my shed I cut a hole in door slightly smaller than the furnace plate I bought (and put the carbon filter stuff between plate and door (it's 10x10" or so hole), as the air has to come from somewhere that it sucks out not sure you can affect that much if passive air as it would just bring it in faster I would think. But I would go with at least the same size as your outlet or slightly bigger, unless you forcing air in then just get the cfm of inlet and outlet close to each other (though again at least same size hole).

Okay man thank you again I will try like 2 3” holes near the bottom of the door to get cool air and will monitor how it goes thank you again very helpful