# Weed smell even with the carbon filter **URL:** \ **Category:** Troubleshooting\ **Created:** [October 31, 2024, 5:05am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428 "2024-10-31T05:05:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Ronb123](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Ronb123](https://ilgmforum.com/u/Ronb123)\ **Post date:** [October 31, 2024, 5:05am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/1 "2024-10-31T05:05:38Z")
I am using a 4” inline fan and a carbon filter in my 3x3 tent exhausted to under my crawlspace and it still smells in my house. What else can I do to knock the smell out? ---
**Author:** ![Serf](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/serf/32/1030048_2.png) [@Serf](https://ilgmforum.com/u/Serf)\ **Post date:** [October 31, 2024, 6:16am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/2 "2024-10-31T06:16:42Z")
I’m in the same boat man. I have a 4" vivosun scrubbing the inside of my tent which then gets scrubbed by a 6" AC infinity and exhuasted but my home smells like a pot farm. I ended up buying a new tent to see if the cheapo is the cause. Both filters are new. I wont know till its all moved. ---
**Author:** ![DanB](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/danb/32/1128709_2.png) [@DanB](https://ilgmforum.com/u/DanB)\ **Post date:** [October 31, 2024, 6:40am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/3 "2024-10-31T06:40:55Z")
@Serf could also try scented dryer sheets in the filter of the EXHAUST to try and mask the smell. In my head I’m looking at it like a dryer vented, moisture and smell get vented out, so why wouldn’t a few dryer sheets help? ---
**Author:** ![Serf](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/serf/32/1030048_2.png) [@Serf](https://ilgmforum.com/u/Serf)\ **Post date:** [October 31, 2024, 6:44am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/4 "2024-10-31T06:44:45Z")
I could give that a try. I have my setup in a area that isnt sealed off from the rest of the house which was my first mistake. Im cleaning out a spare room now that has a sealed door then going to vent into the crawl or something. ---
**Author:** ![DanB](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/danb/32/1128709_2.png) [@DanB](https://ilgmforum.com/u/DanB)\ **Post date:** [October 31, 2024, 6:50am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/5 "2024-10-31T06:50:31Z")
They also have oils an other scented stuff you could try using on the filter itself. I’m not sure of the affect it will have on the filter. But IMHO scented dryer sheets like 5 of them set in layers in the carbon filter I would think would help ---
**Author:** ![Highgrow](https://avatars.discourse-cdn.com/v4/letter/h/d26b3c/32.png) [@Highgrow](https://ilgmforum.com/u/Highgrow)\ **Post date:** [October 31, 2024, 6:51am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/6 "2024-10-31T06:51:12Z")
I believe i read on another thread for the carbon filter to work properly, you have to have negative pressure in ur tent? 🤔 My filter works well in my 2x2 with deal with smell. Not sure if its because of the space size or not though… ✌ ---
**Author:** ![Serf](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/serf/32/1030048_2.png) [@Serf](https://ilgmforum.com/u/Serf)\ **Post date:** [October 31, 2024, 6:53am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/7 "2024-10-31T06:53:03Z")
I think some of the issue is most filters arent vacuum sealed at the plant and just get tossed into bags and a box for sale. I imagine that this could cause the filters to be less effective but im not 100%. My exhaust normally has a weird sweet smell but now into full flower its all flower. ---
**Author:** ![DanB](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/danb/32/1128709_2.png) [@DanB](https://ilgmforum.com/u/DanB)\ **Post date:** [October 31, 2024, 6:54am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/8 "2024-10-31T06:54:43Z")
Was not thinking about the negative pressure, that might be another option ---
**Author:** ![Serf](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/serf/32/1030048_2.png) [@Serf](https://ilgmforum.com/u/Serf)\ **Post date:** [October 31, 2024, 6:54am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/9 "2024-10-31T06:54:45Z")
Yes you do need some neg pressure. I also think there could be tiny holes in ducting that pulls in some unfiltered tent air. I cant see them but I didnt light test the ducting. ---
**Author:** ![Highgrow](https://avatars.discourse-cdn.com/v4/letter/h/d26b3c/32.png) [@Highgrow](https://ilgmforum.com/u/Highgrow)\ **Post date:** [October 31, 2024, 7:00am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/10 "2024-10-31T07:00:59Z")
Ima tryning to find the tread i saw it on for reference. Im by no means an expert on this, just something i saw within the last week. My 2x2 does “suck in” when the exhaust turns on so i have assumed thats what it means to have negative pressure in the tent. 🤷‍♂️✌ ---
**Author:** ![Highgrow](https://avatars.discourse-cdn.com/v4/letter/h/d26b3c/32.png) [@Highgrow](https://ilgmforum.com/u/Highgrow)\ **Post date:** [October 31, 2024, 7:01am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/11 "2024-10-31T07:01:21Z")
That could be a possibility too ---
**Author:** ![OGIncognito](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/ogincognito/32/475294_2.png) [@OGIncognito](https://ilgmforum.com/u/OGIncognito)\ **Post date:** [October 31, 2024, 11:25am UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/12 "2024-10-31T11:25:45Z")
Put some scented dryer sheets in your HVAC registers 🤟 ---
**Author:** ![MikWya](https://avatars.discourse-cdn.com/v4/letter/m/8c91f0/32.png) [@MikWya](https://ilgmforum.com/u/MikWya)\ **Post date:** [October 31, 2024, 12:05pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/13 "2024-10-31T12:05:09Z")
I would think venting into a crawl space under house might increase smell throught house, i have read several threads where people vent into the attic so it escapes out roof vents, i have not tried it yet but will be doing it before i start next grow, have also read carbon filters in your cold air return helps alot, that i will be trying as soon as my plants go into flower. ---
**Author:** ![Sj2019](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/sj2019/32/194189_2.png) [@Sj2019](https://ilgmforum.com/u/Sj2019)\ **Post date:** [October 31, 2024, 12:09pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/14 "2024-10-31T12:09:40Z")
My carbon filter (Vivosun) has washable cloth pre filter that I washed prior to my grow. Also they advised to wrap tape around the area where the carbon filter meets the exhaust fan. And a clamp is included for the dryer vent exhaust tube connection to the fan. Just advice to check to make sure you have a good seal on the exhaust equipment ✌ ---
**Author:** ![Ronb123](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Ronb123](https://ilgmforum.com/u/Ronb123)\ **Post date:** [October 31, 2024, 12:57pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/15 "2024-10-31T12:57:26Z")
Thanks to all for the advice. I will definitely take the connection to the carbon filter and use dryer sheets. As far as the negative pressure, I am constantly adjusting humidity in my tent. I always have at least one vent open which j would think would cancel out any negative pressure. Thoughts? ---
**Author:** ![Serf](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/serf/32/1030048_2.png) [@Serf](https://ilgmforum.com/u/Serf)\ **Post date:** [October 31, 2024, 1:20pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/16 "2024-10-31T13:20:22Z")
Neg pressure will increase as your fan speed increases. Mine is set to idle at speed 2 and max at speed 7 of 10 when its triggered above 60% rH or 82°. Even with a base vent open it can still suck in the tent like crazy. ---
**Author:** ![Sj2019](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/sj2019/32/194189_2.png) [@Sj2019](https://ilgmforum.com/u/Sj2019)\ **Post date:** [October 31, 2024, 1:32pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/17 "2024-10-31T13:32:18Z")
I have extra round ventilation ports that are totally closed. Then I have 2 rectangle shaped mesh vents that I only have about 1 to 2 inches uncovered at this point in my grow, she is only 3 weeks old. I will close those off when she gets bigger and smelly to get the negative pressure. ---
**Author:** ![kellydans](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/kellydans/32/580751_2.png) [@kellydans](https://ilgmforum.com/u/kellydans)\ **Post date:** [October 31, 2024, 1:33pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/18 "2024-10-31T13:33:31Z")
If you could exhaust outside would be a better choice , install a dryer vent to the outside. Also I like to buy a new filter twice a year. ---
**Author:** ![Ronb123](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Ronb123](https://ilgmforum.com/u/Ronb123)\ **Post date:** [October 31, 2024, 3:46pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/19 "2024-10-31T15:46:18Z")
Thanks again to all. I got some good stuff from you guys ---
**Author:** ![merlin44](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/merlin44/32/1090518_2.png) [@merlin44](https://ilgmforum.com/u/merlin44)\ **Post date:** [October 31, 2024, 3:50pm UTC](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428/20 "2024-10-31T15:50:57Z")
I just reread one of your posts. For an exhaust fan to be effective, you must have an inlet for makeup air. To contain and control odor you must be pulling air out of the tent and filtering it. If the inlet port(s) are just open holes, then smell will migrate out unless the fan is running. [Next page](https://ilgmforum.com/t/weed-smell-even-with-the-carbon-filter/115428.md?page=2)