Do I need a intake fan for a 4x4?

Do you guys think I can get away without putting an intake fan in my 4 x 4 tent? I have a carbon filter attached to an exhaust fan so do you think I can get away without putting an intake fan? Or is it a must in a 4x4. Also if you think I can get away without putting an intake fan in do I have to keep the floor vents open or can they at least remained closed during lights out? I have a bit of negative pressure but how do I know if it’s too much negative pressure?

I just use an exhaust fan, T6, works perfectly for my two tents, 4x4 and 2x5

I would set one up just in case it's needed for heat/humidity or negative pressure.

Dreminen169 said:

Do you guys think I can get away without putting an intake fan in my 4 x 4 tent? I have a carbon filter attached to an exhaust fan so do you think I can get away without putting an intake fan? Or is it a must in a 4x4. Also if you think I can get away without putting an intake fan in do I have to keep the floor vents open or can they at least remained closed during lights out? I have a bit of negative pressure but how do I know if it’s too much negative pressure?

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You don't need to even use the floor vents, you can just run some ducting out of a lower port and light proof it if you want. You won't need an intake fan unless you're doing something unusual.

HydroKid239 said:

I would set one up just in case it's needed for heat/humidity or negative pressure.

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I’m already getting a decent amount of negative pressure with exhaust fan on low and no intake fan. Would adding a intake take the negative pressure worse of better?

Dreminen169 said:

I’m already getting a decent amount of negative pressure with exhaust fan on low and no intake fan. Would adding a intake take the negative pressure worse of better?

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You can go cost effective and just run a vacuum hose (if you have a spare) thru one of the smaller ports on the lower end of the tent. If you run it out the back of the tent you won't really have to worry about light leak.

to answer the question adding an active intake would take from your negative pressure.. but to get it back, just bump up the exhaust a little higher.

Unless you are running co2 an intake can be useful in replenishing co2 in the tent.

Fun fact for non-SoCal people - Fall is our summer.
Hot Santa Ana winds, single digit humidity all day. Then cool, precipitous fog all night (here locally - most places stay hot all night)

(Since installing a new exhaust fan - T6)
I have 3 ducts running into the tent - Two 4" and a 6" - all light proofed.
Two of the duct runs are short - a fan would be pointless, so they're purely passive intakes.
One run pulls fresh air from a window and is much longer,
so I do run a cheap, 4" booster fan inside the tent to help manage temps & humidity.