HELP! CFM on the fan blowing air in the tent is different than the fan blowing air out?

[TheShmoopler]

Good morning!

I'm going to start my first grow here very soon in San Diego and half of the parts I'm using for my tent are from my brothers previous set up. I have a 4' x 4' x 6.5' tent that I purchased and I'm using my brothers 6-Inch 240 CFM Air Duct Inline Fanto bring air into the tent and his 6-Inch Inline Exhaustingthat google says has a 442 CFM with a speed controller. I've noticed that on the "High" setting the exhaust fan will take so much air out that it wil literally vacuum the tent and the sides will start closing in, but on the low setting there seems to be a fine balance. Is this vacuuming effect non-desirable, and if it is, is it OK to just balance them out by having the high CFM fan on the low setting? How do I tell if enough air is being recycled?

Also, I was hoping to be up and running this weekend but it's hot as ball here in San Diego and the tempurature in my tent is 90 degrees with 15% humidity. Can you recommend a good humidifier that would cool things down and bring up the humidity? I saw a guide for a swamp cooler on the humidity page but it looks like it might take some time to get the parts together and I'd rather just buy something flat out. Thank you!

6-Inch 240 CFM Air Duct Inline Hydroponic Booster Fan: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
6-Inch High CFM Inline Exhausting Fan: https://www.zenhydro.com/ipower-glfa...EaAk1WEALw_wcB

[Campesino]

The vacuum effect is desirable for controlling smell and environmental factors. It is generally recommended to have exhaust CFM be higher than intake CFM. Your set-up seems fine, especially with the ability to adjust exhaust.
A swamp cooler may solve your problems now, but plants will start producing their own humidity and your problem will be primarily heat. Your lights, grow media, venitaltion set-up (where do you vent to and draw from, and other practices will need to be considered to determine needs for adjusting heat and humidity.

[Tika]

Couldn't say it better than Campesino. A little suck on the sides of the tent is good.

[RosettaStoned]

I wouldnt use an active intake.

[Chefbjy]

I'm with Rosetta if your exhaust is sucking in the tent walls without the active intake it should be fine. If using an active intake the exhaust can be the same dimensions. With a passive intake the intake should be 2-3 times bigger then exhaust hole.