Exhaust vs active intake fans ratio

Hello everyone,

I have read different things from different sources and I am confused about whether exhaust fan ve intake fan should be equal or active intake fans can be a little bit small. I have an exhaust fan with carbon filter that is adjustable to 82 and 105CFM. Intake fan is 63CFM.
I set up exhaust fan to 82CFM and intake fan run at 63CFM. I also have oscillator fan inside tent. Tent dimensions are 2x2x4 so 82CFM i think more than enough.

So intake fan runs %30 less speed than exhaust fan. Is it ok or should I match the CFM values of exhaust and intake fans?

Don't match the CFM for both fans. You'll find it won't work that way and you'll end up with positive pressure, your tent will balloon and you'll end up blowing all the skunk right out into the air of your house or wherever your grow is.

Your filter setup and whatever ducting reduces the efficiency of your exhaust fan, but also you want to keep a little negative pressure.

I have two matching fans, a Cloudline T6 and a S6. To make the ventilation run successfully I'm always running the intake (S6) at a rate that's about half of the exhaust fan. More than that it starts to get into that zone where it leaks air out of the tent through the zipper/seams or other not perfectly sealed vents.

Thank you so much, maybe i can increase exhasut fans rate to 105CFM, it makes almost %50 percent between them. But 105CFM means renewing the air twice per minute in the tent. I think i will try both alternatives and see what happens

mnw said:

Thank you so much, maybe i can increase exhasut fans rate to 105CFM, it makes almost %50 percent between them. But 105CFM means renewing the air twice per minute in the tent. I think i will try both alternatives and see what happens

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It takes a bit of jockeying to figure it out but after a while you know your settings. I do alter my exhaust fan depending on ambient conditions in my tent, so if I've watered recently and my humidity goes up 8 points, I move my fan from running at '6' up to running at 8 and then I bump up my intake a bit too. If I think it's pulling too much air through the tent, I drop it back and match the intake downwards as well.