Do i need a intake fan

If i am gonna have a 170 CFM fan pulling air out through a carbon filter do i need a intake fan if i have a vent to outside??
In a 4x2 room
thanks
peace out

its prolly a good idea

you need intake and outake.

i have one 4 inch fan: that pulls exhaust from the top, then it goes through the fan which pushes the air through a carbon scrubber.

i know an extra fan to supply air would be a bonus, but what i did was just run some 4 inch flex duct out a bottom vent in my tent and i place the intake of that closest to my dehumidifier so it keeps my humidity down inside the tent

Ok thanks people...there goes another 50.00