Still have smell with carbon filter

Discussion in 'Grow Room Design/Setup' started by Walla2Walla, Feb 22, 2016.

  1. Why can I still smell that sweet odor coming from my exhaust. I have a 4x4x7 tent with 6 in fan pulling air through a carbon filter then through a hood then exhaust. But the smell isn't being scrubbed. (Most of it is but I can still smell bud)..

    Carbon filter-> ducting -> light hood-> ducting -> exhaust

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  2. You might have a have a fan dedicated to the scrubber, in the tent. With your set up it's only making 1 pass
  3. So have a dedicated fan scrubbing and a dedicated fan for cooling the hood?

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  4. I'm a newbie grower but I design carbon filtration for plastic extrusion applications....A 6" fan is too many cfm's for that space. Use a voltage regulator to slow it down and get better 'dwell time' in the carbon. With too many cfm's it rushes through the carbon too quickly.
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  5. And you might have an air leak in your piping after the filter check to see all joints...
  6. Hoods can leak. That's why I push through my hood with the fan. Also consider that not all carbon filters are created equally. If your carbon filter is rated for 400-600cfms and you have to slow down your exhaust to get it to work properly then you need a better filter. I understand if you have to buy a cheap filter to get through your first grow but after that you should be able to invest in something decent.
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  7. I totally agree with Thicken Dense! Really, I have never understood why people like pulling air through their hood(s). If you push air through your hood(s) you will never have to worry about leaking or smelling anything. Cool tubes, cool hood reflectors are to lower the temperature of your grow room when using high heat producing grow light(s) and nothing more. So they shouldn't ever be hooked into your filtering system. Even the best sealed tube(s) or hood(s) will leak sooner or later. As any type of seal, rubber, silicone, neoprene, aluminum, cork, etc, etc: will over-time absorb your weed(s) humidifier air, and that residue buildup will leak, period!

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  8. #8 Dankeddie, Feb 24, 2016
    Last edited by a moderator: Feb 24, 2016
    I pull air through my hood from 2 separate tents both equiped with its own carbon filter and fan hanging on the inside above the hood. Outside the tents I have a coupler and I ran the duct in into the closet attic space and crawled the ducting to a opening on the side of the house in the attic. I walk outside to check the smell from that vent.

    I did have a leak one time and I found there was not a snug connection on the side of the fan that was pushing air out of the tent.

    Use duct tape on every connection from the ducting to hood or ducting to the fan and you will have no smell I promise.
  9. Drawing hot air through the fan will shorten its life.

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  10. So it would be best to separate the 2? Have my 6 in in line fan pulling through the scrubber and out of the tent. Then have a booster fan pulling cool air from outside the tent, blowing into the hood and exhausting outside the tent. Having it blowing into the hood would create positive pressure so no smell would leak right? Could I also have those 2 connect into a Y connector so I only have 1 hole to drill into the attic or floor?

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  11. Nobody has asked the important question yet. What is your filter? Brand and dimensions? Dwell time is definitely a factor, but if you have a small 2600 can filter rated for like 50-100 cfm, it's not gonna cut it, but if you have a massive filter rated at like 400 cfm, then your 6 inch fan isn't the issue. Give us the whole story.
  12. im in this boat. I have a big charcoal activated carbon filter. Then its air cooled hood. Then its 440cfm 6inch fan sucking obv. negative pressure achieved.

    I can smell my plants. Blep

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  13. You may have a leak in your hood. It's sucking stinky air through the gaps on the glass and straight out without being scrubbed. You need to push air through the hood instead so any leaks go back in the tent to eventually get scrubbed.
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  14. i can tell ya right now the hood isnt sealed, put some duct tape on the crack though.

    Are you suggesting i push air thru the hood and have another cfm sucking thru the carbon filter?

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  15. This was smell proof pushing thru the hood instead of sucking But airflow was a little bit slow. I'll use a seperate fan for my hood like your suggesting next time though for more airflow.
  16. I think the only reason that was smell proff is because your plants are in veg.
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  17. I just smoke in my room so it kind of all mixes together ? But I do have sweet smell coming from my exhaust fan as well. Reading the posts, I might have too big of filter for the fan. But then again, I don't know if I have it set up properly. Due to the size, I have to keep it standing up on the floor.

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