Air intake. Negative air pressure

Having set myself up with a basic 1.5mx1.5x2m tent and equipped it with an intake exhaust fan (452CFM) and carbon filter.

When the filter runs I can see the sides of the tent come in and pull right. I think this is causing negative pressure inside the tent.

What would be the best way to fix this?

Is have tried running it with all 3 side vents open but it didn’t appear to help.

If you already have the vents open the only thing left to do is to turn down your exhaust fan.

Use a speed controller remember 450 cubic feet per minute is a lot of air in a tiny space.

Filtered intake air in the bottom vent of tent

Negative air pressure isn’t a bad thing, means your exhaust system is working.


Thanks everyone. I’ll either add a speed controller or add an intake fan. When adding a intake fan should I match my exhaust fan or find one that put in a little more then is been taken out? Anyone have a recommendation for a fan or speed controller?

Thanks again for down under.

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If i understood what I read correctly. You will want a smaller intake so it doesn’t bog down your exhaust fan with more air than it can pull out. Too much air on the intake will cause your tent to expand and might bust some seams

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Thanks. If I buy something like the Can-Fan RS 125 would allow air to be pumped in at a slightly lower rate than it’s currently being extracted?

After some research, I’m lead to believe that to correctly match an intake fan is to divide the CFM of the extraction by 4 and that will give me what I need in out of an intake fan.

If that is correct I’ll need something like a 120CFM intake fan. 452/4=113