Fan CFM setting for tent (+ filter & ducting)

Velocifasor

New Member
Hello. I'm setting up my first grow tent (a 3x3x6.5). I live where it's illegal to grow so I have to keep odor as close to non-existent as possible.

I'm using a 400W Led panel and I bought a 5'' coconut-carbon filter rated 250 CFM (coconut carbon is supposed to be 15-25% better than regular carbon) and a 5'' extractor fan (with two settings 130 and 165 CFM).

1. I understand the fan should be enough (the air in the tent would be replaced about 2.7 times per minute at the highest speed) but I don't know if moving the air too quickly through the filter is actually a bad idea (as opposed to moving it slower thus being in contact with the carbon for longer).

2. Is filter>extractor fan>ducting to the outside the best possible setting? Filter and extractor inside the tent.

3. Does it matter wether the air is sucked or pushed to the filter? I'm considering a second fan/filter pair for the room if the smell manages to escape the tent.

It's a 3 room apt. I'm considering putting rubber lined gaskets on all doors and windows to prevent filtrations. The front door opens into the living room, about 30ft away from the tent (which would also be in a separate room and with a 9ft hallway in between).

What else could I improve on?
 
Last edited:

Grow So High

Well-Known Member
To be honest it seems like you have it pretty much figured out. I run a 4x4 with a 400 cfm exhaust fan. Filter/fan/ducting inside the tent with no smell until the tent is open. I like your idea with putting rubber gaskets on the doors and windows. Based on your situation I think it wouldn’t be a bad idea to get an extra filter for the room itself because once you open that tent in flower it’s going to be looooouuud lol and I would probably be paranoid if I were trying to be low key in an apartment.
 

coreywebster

Well-Known Member
1. Less airflow if you can run it and still be good with temps will prolong the life of the filter.

2. yes

3. If your doing things right, as in removing the air and heat from the room entirely then you can't push through the filter unless its an inline filter which has connections at both ends, those are less common.

4. Again if your doing things right you would be removing that heat, high humidity air, depleted co2 air from the house via a window, chimney, vent or whatever. This keeps your environment in check and co2 refreshed.
So considering that you do not want to be sealing your windows and doors unless your also running an intake fan. All the air you remove has to be replaced, normally passively, if you seal all gaps where will new air come from and if new air cant get in the old air cant get out since you can only create so much negative pressure in a room before you start overworking your fan.

If you actively extract and passively intake then you have some negative pressure which stops stink leaking around your whole apartment.
If you handle your plants/brush against them and walk through your apartment the stink will stick to you and your apartment will smell for a short time.

If you cant afford to have any smell then have a separate set of cloths that you wear in the grow room, never answer the door on harvest day, bag up your cloths when your done with them.
Cover your hair, it will absorb stink. Wear a dust mask when trimming or you will smell weed everywhere you go, because its in your nose.
 

Velocifasor

New Member
To be honest it seems like you have it pretty much figured out. I run a 4x4 with a 400 cfm exhaust fan. Filter/fan/ducting inside the tent with no smell until the tent is open. I like your idea with putting rubber gaskets on the doors and windows. Based on your situation I think it wouldn’t be a bad idea to get an extra filter for the room itself because once you open that tent in flower it’s going to be looooouuud lol and I would probably be paranoid if I were trying to be low key in an apartment.
Thanks. Should I get a fan/filter that can extract all the air in the room in 2 minutes too or something smaller? Considering I'd use it only in those situations.

1. Less airflow if you can run it and still be good with temps will prolong the life of the filter.

2. yes

3. If your doing things right, as in removing the air and heat from the room entirely then you can't push through the filter unless its an inline filter which has connections at both ends, those are less common.

4. Again if your doing things right you would be removing that heat, high humidity air, depleted co2 air from the house via a window, chimney, vent or whatever. This keeps your environment in check and co2 refreshed.
So considering that you do not want to be sealing your windows and doors unless your also running an intake fan. All the air you remove has to be replaced, normally passively, if you seal all gaps where will new air come from and if new air cant get in the old air cant get out since you can only create so much negative pressure in a room before you start overworking your fan.

If you actively extract and passively intake then you have some negative pressure which stops stink leaking around your whole apartment.
If you handle your plants/brush against them and walk through your apartment the stink will stick to you and your apartment will smell for a short time.

If you cant afford to have any smell then have a separate set of cloths that you wear in the grow room, never answer the door on harvest day, bag up your cloths when your done with them.
Cover your hair, it will absorb stink. Wear a dust mask when trimming or you will smell weed everywhere you go, because its in your nose.
Thanks. Definitely did not think about the clothes.
 
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