Indoor grow help needed please-Carbon air filter

Happy Growing GrowMasters, quick question about carbon filtration; I have a very small indoor room and I need to eliminate the odor once starting to flower. Any suggestions on equipment?

Room is less than 200 sq/ft. I was looking into a seperate fan and separate filter for the room, carbon filter 4”.

Any suggestions?

Thanks guys-

get something like this
comes with the exhaust fan and carbon air filter.
i have some smelly plants right now and the smell doesnt get past the tent it is in with this thing

that is the exact one i use, its like 180 for the bundle, so not too much, and its definitely quality product, works like a charm. has for about a year now, still workin like new

the 4" bundle is only 140, should work just as well


Awesome, thanks Hershey!!

Use the above kit with the filter located in the grow room, and then connect the exhaust fan with the supplied flex to the filter. I prefer to locate the fan outside the tent, but inside will work OK. You will want to adjust the air intake into the room to be a little less than the exhaust is pulling out. This way the negative pressure in the room will hold the smell in the room, the only way out for the smelly air is through the filter that scrubs the smell out of the air on its way out.

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i agree with havin it outside to save some space.

this is how i have it set up.

so i put one piece of tubing coming out of a top vent and pulling air out with the fan pushing it through the filter

obviously by doing this, it will cause the walls to compress, and can be hard to draw air into the tent
so to counter that negative, i also put a piece of tubing in a lower vent.
it should be bent to prevent light leaks but also allowing air in the the opposite side through the bottom.
by putting these at opposite ends of the tent, like shown.
one sucking from the top and one simply leaving an opening for air to come in through the bottom
this allows for better air flow throughout the entire tent

and like i said, the only time i smell the ridiculous stench from the buds inside, is when im poking my head in to tend to it.


Im a little confused :sweat_smile: i thought the carbon filter had to be on the inside of the tent to scrub out the stinch? Or am i overlooking something else that was said? :thinking:

At 200 square feet. You may want to consider stepping up to a 6 inch fan filler combo. Let’s say that you are dialed in at 150 cfm for the exhaust and filter. The 4 or 6 inch either kit will give you that air flow. But with the speed controls that ACI gives on its fan. The 6 inch fan would be much quieter, and the filter will last 2-3 times longer. This may maybe worth the extra price to you?
200 square foot is a large area, and if it has a 8 foot ceiling that is 1600 cubic foot area. To get a complete change of air in that area every 5 minutes. It will require 320 cfm of air movement, and of course 160 cfm will only give a change every 10 minutes. For a growing area you really should have a complete change of air every 2 to 5 minutes.


You can place the filter on the outside of the tent, or the discharge side of the fan. But by doing this you reverse the air flow through the filter, and it flows from inside out. This reduces the inlet filter surface area, since the inside diameter of the filter is smaller than the outside diameter, and the pre filter sock on the outside of the filter will be useless when the air flow is reversed.

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Ohh ok i think i see what ur saying. Mine is on the inside of the tent per recommendation of the company. I might try and switch it around my next grow to give me more vertical space in my tent. Good info :metal::saluting_face:

Let me introduce you to my filter in a bucket. By using the bucket to contain the filter I can maintain the correct air flow direction through the filter while removing it from the grow area. Also you can use the fan to push or pull through the filter. This idea has gone through a couple evolutions. Here is the basic set up to obtain the bucket set up. The air inlet is on the bottom side, and the air outlet is on the top. So that the outside to inside air flow is maintained through the filter.

Here it is with a 4 inch inlet and outlet, and the fan pulling through.

This is how it is being used now. Hanging in the ceiling with the fan pushing into the filter, and now with a 6 inch inlet. This works very well, and is super quiet also this way. The second fan in the last picture is the inlet fan.


Nice set up there!! I understand better now. The fan is pulling air in (through the bottom) and filtering out the top through the carbon filter.

Probably a dumb question but thats used in an open grow room? This is something i can look into for when i convert my spare bedroom into a grow room. Very nice!

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The filter and exhaust fan are just ducted from the top of a 2x3 tent. The inlet fan is ducted into the tent as well, but the intake is delivering a little less air than the exhaust is pulling out. This creates a negative pressure in the tent that locks in the odors.


u can honestly put the carbon filter wherever u want as long as the airflow gets passed through it. it can be the enter point inside the tent and have the fan sucking from the carbon filter to the outside of the tent
or ir can be the exit point by placing it outside the tent and having the fan blow into it. i choose the outside to save some space and reduce clutter inside the tent.
u could use the space for the light if u by chance need to raise the light due to the plants height. and it just generally looks neater in the tent this way. but thats ur choice to make.
all works the same either way honestly.

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Yes you can put the carbon filter anywhere you want, as long as it is located at the beginning or end of the duct run. Since as it is out of the box, it only has one connection. By placing it in a container the filter maintains correct air flow direction. And with a dedicated inlet and outlet it can truly be placed anywhere, including the middle of the duct run. This may work better in some applications, as well as extending filter life. I am not running down anyone else’s technique. Just putting the filter in a bucket out there for consideration.

Outta likes but good to know! Thanks @Ickey and @Hershy420 i honestly thought it HAD to be inside the tent… the more ya know :saluting_face:

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bleh, nobody reads the manufacturers recommendations these days, we use the interwebs now for all that information.

those papers that come in the box go straight to the trash these days.

i hear u can get some kind of mutated covid disease even jus touching those papers with ur hands now
i highly recommend using 6 layers of gloves and a tongs, a very long tongs, maybe even 2… to slowly and carefully dispose of those instructions and recommendation papers as fast an efficiently as possible than go straight to the sink and wash up vigorously and than go straight to the interwebs for any information u seek these days :+1:
stay safe out there :call_me_hand:

I love it! :rofl::rofl:

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When installing the carbon filter on the exhaust end of the ductwork, keep in mind the dust and debris will eventually build up internally on the carbon filter.

This is why carbon filters come with a prefilter. This is replaceable when the debris builds up, and begins to restrict airflow.

I prefer the carbon filter on the intake only side, for this reason.