Carbon filter- blow air into or pull air out?

A2Michigan said:

Am I suppose to blow air in or pull air out? Everything I’ve read online says to pull air out. I even contacted Phresh filters and they said I should be blowing air into it. What are your thoughts? I’m going to be getting a tent with 1400 cubic feet and I want to exhaust the air and minimize the smell completely. Any info will help!

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Id suggest doing what Phresh tell you how to use the filters they build.
In saying that I'm in a tent, so I want negative air pressure so suck air through it.

Seem to have a different frame of reference than some here. When I asked what is wrong with positive pressure I was thinking positive into the filter rather than pulling a negative pressure from the back side of the filter. Pressurizing your room? Nope, probably not a good idea for most.

Always blow air through them

Lucky Luke said:

Id suggest doing what Phresh tell you how to use the filters they build.
In saying that I'm in a tent, so I want negative air pressure so suck air through it.

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That's got nothing to do with negative pressure

I've had the best results doing both at the same time. Filter in the tent-ducting-fan-ducting-filter. Works great, zero smell. Picked up a wind speed meter for a few bucks on the 'zon to double check the actual cfm. I always get a filter with a higher cfm rating than the fan so I think that helps too.

doesn't matter it's purely aesthetics i believe as well as space issues but you still are doing the same which is it has to go through the filter somehow to even work. most setups i see is pulling the air out of the filter. i am not 100% certain on this but i would highly assume the only thing that matters the most is if your hose has kinks so if you have to bend your tube you need to suffice for that. think a water hose that is straight versus a hose with a bend and how the water coming out of it is affected i'd assume the same thing with air flow.

f series said:

That's got nothing to do with negative pressure

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true u can get neg pressure either way.

Im sure the outer sock works better if ur pulling into though. Would keep less dust and stuff from getting into the charcoal filter.

Blowing air into a filter or sucking air through a filter will not effect how well a carbon filter will work. The velocity through the filter will. The slower the air speed the more time the filter has to grab the molecules out of the air. A lousy flow path will restrict your airflow through the system but it will increase how well your filter works. Might just be a few percent and not noticeable or substantial depending on your equipment. The downside of restricted airflow will be less cooling in your grow area and less air changes reducing humidity and bringing in fresh CO2.

I've done both ways

Both the same effectiveness. First 3 grows i had filter and fan inside tent, with the air being sucked thru the filter then out the tent as in pic #1. The fan being inside the tent adds more heat, and everything is quieter that way -if heat is not an issue for you

This run I have everything outside the tent , ducting from the tent to the fan outside creating negative pressure in the tent and blowing air into the filter and it works just as well with no added heat from the fan. Lots of extra space at the top of the tent also is an additional benefit, but essentially both ways eliminated smell so take ur pick

I personally use 2 carbon scrubbers for every room I have. One for intake and one for exhaust. They do a great job minimizing the smell. My rooms are about 9x7, and I can’t smell a thing the next room over.

there is a pre filter wrapped around your carbon filter so you want it on your INTAKE side of the fan
unless you add a seperate pre-filter on the intake, you could then remove the pre-filter and have the carbon can on the exhaust

other wise you potentially clogging your charcoal filter because the pre filter is supposed to prevent small particles from getting past and into the pores of the charcoal