Carbon Filter Bottom of Tent?

Hello,
Can I place my carbon filter on the bottom of the tent?
The reason is because I'm annoyed the carbon filter is taking up 1 foot of space vertically in my 5x5 tent.
This is so much wasted room I could grow my plant taller.
25sqft wasted for probably 3sqft of carbon filter and ducting.

CO2 is heavier than air, so it's bad to put on the floor and pull air out that way?
I exhaust my air outside my house anyways (I use the carbon filter to just make it stealthier), so solution seems difficult..
On the floor or I remove the filter altogether and just pull air out of the top of the tent with the fan outside the tent seem like the only options.

Any ideas? Advice in general

The CO2 concerns are unwarranted, even moderate air movement within a tent is enough to keep CO2 evenly distributed.
The only potential disadvantage of having the filter on the bottom is that you're extracting the coolest air rather than the hotter air at the top.
That may be a good thing or a bad thing depending on your environment.

I've done it in my tents for a couple grows with no real negative impact. I run a 3x3 tray in my 4x4 tent so that space is unused anyway. In my 3x3 tent, I run a 24x24 tray, so same thing there. In the big tent, I use a small fan blowing down on the led driver to move warm air down and assist with the circulation.

4x4

3x3

Here’s my solution


can66 took up too much space. Seran wrap gets it airtight.

Billy the Mountain said:

The CO2 concerns are unwarranted, even moderate air movement within a tent is enough to keep CO2 evenly distributed.
The only potential disadvantage of having the filter on the bottom is that you're extracting the coolest air rather than the hotter air at the top.
That may be a good thing or a bad thing depending on your environment.

Click to expand...

You do realize that the constant air movement that keeps the CO2 mixed in also mixes in the rest of the air keeping temps pretty much even all over right?

OldMedUser said:

You do realize that the constant air movement that keeps the CO2 mixed in also mixes in the rest of the air keeping temps pretty much even all over right?

Click to expand...

I understand your point, and it likely depends on the amount of air movement.

In my tents, with circulation fans running, it's always few degrees warmer
at the top of the tent vs. the floor.

CO2 levels are the same throughout.

Set the fan and filter outside the tent and have the fan pull air from the top of the tent.

If you are worried about temp buildup, then just get a small inline fan and backflow damper to exhaust where you are already exhausting.

I’ve kept the Filter on the floor for the last 13 years, keeps the room smelling fresh and I draw the cooler air in from the top with a 4” vent tube running from outside and to about midway in the tent. Works for me, but your mileage may vary.

I turned mine into an inline filter by enclosing it in a cardboard box. It now sits on top of the tent.

RustyR said:

Hello,
Can I place my carbon filter on the bottom of the tent?
The reason is because I'm annoyed the carbon filter is taking up 1 foot of space vertically in my 5x5 tent.
This is so much wasted room I could grow my plant taller.
25sqft wasted for probably 3sqft of carbon filter and ducting.

CO2 is heavier than air, so it's bad to put on the floor and pull air out that way?
I exhaust my air outside my house anyways (I use the carbon filter to just make it stealthier), so solution seems difficult..
On the floor or I remove the filter altogether and just pull air out of the top of the tent with the fan outside the tent seem like the only options.

Any ideas? Advice in general

Click to expand...

It'll work fine at the bottom if you have decent air circulation in the tent to mix up the air keeping temps pretty much the same top and bottom. What is not a good idea is to have the filter outside the tent and pump the air into the filter as dust etc will plug up the surface of the carbon creating a lot of back pressure and rendering the filter useless. The same can happen to one that doesn't have a pre-filter sock over it so it's a good idea to use the one that should have come with the filter. If you don't have one you can wrap the filter with a double layer of cheesecloth to do that chore.

I bought an oversized filter because of a tip from the owner of the grow store. He said to wrap the bottom half of the filter with saran wrap until you start to get stink at the exhaust then unwrap that and wrap the top half. Running my 400cfm fan at half speed would give less than 200cfm due to the restriction of the filter which is rated at 600cfm so 300cfm with half covered. My exhaust fan is controlled by a temp/rh unit so it only runs when it's told to by the unit which isn't often as my grow room in under the house in an unheated basement and cool even in the summer.

I never did use the $170 filter so it sits in it's box all sealed up.

I mean are you really going to have your lights to the ceiling and grow plants that high and still get good lower nugs?
Probably not.

It's a fairly common thing to have space up top used by extractor and filter and it doesn't really impact most folks yield.

But if you want to have ot on the floor then crack on, many do and it can be useful.

Or you could buy an inline filter and have it outside the tent, or you could sack the filter off if it's safe to do so, ie you're not going to get robbed or busted..