Passive Intake Air Filter?

What material should I use to keep dust and contaminants out of my tent?

Hmmm... I'm guessing the same material they use for carbon filters. Try getting that, i'm sure you can buy it seperately.

What about a cheap k&n style filter from a car. One of those cold air dooouuup filters

Big smo said:

What about a cheap k&n style filter from a car. One of those cold air dooouuup filters

Click to expand...

this is what i use get a 4inch one meant for a truck got mine at wallyword for $30

Furnace filters will work. Or a HEPA furnace filter if you wanna spend the cash

I don't know how much you want to fiIter out but I use a simple good ol' dollar store nylon stocking. I wrap it around outside of the tent part of the ducting that intakes air. I have a velcro flap I can open on the tent, and the screen mesh covering it isn't as tight (size of the holes) as the stocking, and it works well for me. Tent is in the garage where my gf spray paints and stuff, and my plants are still always clean!

I say furnace filters. i picked one up at the hardware store that's reusable/ washable. i originally was just taping it over my intake, but I've since built a frame to hold it.
like this, around $20>

The furnace filter I used looks just like a green scotch brite pad. I used a 6" hole saw to trace the diameter with a knife and just shoved 2 pieces into the end of the 6" duct. I also bought a 2x3' sheet of activated charcoal that was flexable like the filter but only 1/4" thick. When the fans were off I didn't want any smell to leach back out to the room. It helped sorta.

Just use a stocking. My tents have mesh already over the vents.