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4'x4'x6'2" tent - Passive intake vs active with a filter


New Member
As the title states I am looking at going away from passive intake (vents) to an active style intake with another fan and an intake filter. I know a good bit about fans and needing a static pressure in order to pull through a filter however I was looking at using an axial fan instead of the standard inline fan which is commonly used for exhaust through a carbon filter.

Where I am starting to have questions is what brand of filter, how much difference does the filter have on the overall cleanliness of the room seeing how the passive vents have a screen on them.

Any input/advice would be outstanding!


New Member
First question: Do you have an actual like fabric tent? If so, use tape for what I'm about to say. If you are using a wooden box, cabinet, or room in general, nail it down, or build a little holder for it.

My advice is to simply go online and look up HEPA filters. If you're not looking to eliminate more smell, a HEPA filter is MUCH cheaper than a whole new fan and carbon filter. You can buy up to like MERV 13 (MERV is the rating system for how good the HEPA filter is, can't remember what it stands for off the top of my head right now) for pretty cheap. Above MERV 13 is like industrial use filters and will cost a whole heap of money. But, they come in all different sizes and will filter out any crap that's coming into your tent, with the exception of smell. Most last a few months to a year, or more, and will do what it sounds like you want them to do! You can remain passive, and the filters normal pressure drop starts at .25" of water, and they suggest replacing the filter at 1.0" pressure drop. It's what I'm building my room to do, and it'll also keep out pollen or airborne bugs and stuff. Which is great if you happen to have a male plant for breeding purposes or whatnot, and it's nuts burst. A side bonus of adding the filter is that the air in your room/house will get a nice little trip through an extra filter, and you may see some welcome differences in air quality in your home. Good luck!
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