Inline fan back-flowing when scrubber attached?

Discussion in 'Growing Marijuana Indoors' started by MedicatedWarrior235, Jun 29, 2019.

  1. First of all, I’m using a DIY scrubber because (1) it’s mainly just for my girlfriends benefit, we live somewhere isolated and (2) I can’t really justify purchasing a scrubber.

    I have a Vivosun fan, not sure of the model but can check if needed. It’s definitely not super expensive or top of the line but it has a greater CFM rate than required for my area.

    My question is, when I attach the scrubber, you can audibly hear the fan working harder and it feels like the current gets (somewhat) reversed. You can definitely feel air flowing through the activated carbon but the flow is certainly decreased.

    Will post pics of scrubber too if needed, just wondering if it’s even something I should worry about or if it will still be effective in removing odor.
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  2. Carbon filters exhibit resistance to air flow, which naturally decreases air flow.
    A fan must work harder, and will exhaust much less, with a carbon filter attached.
    There won't be an air flow reversal, just a decrease.
  3. You definitely connected it the correct way round? The side without the scrubber attached should be blowing air our not sucking it in, it's just when you say you can definitely feel air flowing through the carbon makes it sounds like you are blowing air through rather the air being sucked through it, just checking!
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  4. I’m positive the direction is right. I’m definitely feeling exhaust through the other side of the filter, it’s just considerably decreased. If that makes sense. It’s not a TOTAL reversal, just that a lot LESS air is going through than before connecting the filter. Makes sense it would make the fam work harder I just wasn’t sure if what I was experiencing is normal. Sounds like it though. I’m glad I got one with a higher CFM than necessary lol.
  5. #5 Fataqui, Jun 29, 2019
    Last edited: Jun 29, 2019
    Is your grow space a tent? If it is, having a inline fan blowing air into your tent and just having a CF without having a exhaust fan pulling the smelly air through the CF will always cause the inline fan to work much harder because besides pushing new air into the tent it will also have to keep air from being pushed back into the inline opening, because the CF is causing an air flow restriction. So the tent is being blown up like a balloon. And when that happens, you are in fact not filtering all the smells from your grow tent because a lot of those smells will escape through the grow tents stitching and seams, due to the ballooning effect. Anyway... if you only have one fan, your best bet is using a negative pressure system. You do that by having your one fan suck air through you CF and then exhausting that smelly air, and then just leave your inline vent open, and the fan sucking the air out of your grow tent through your CF will remove all the smells from your grow tent while pulling fresh air in at the same time. But if you do that, just make sure that you place a small fan on the inside of the tent close to the inline opening to push the fresh air being pulled in to the other side of your grow tent, so you don't create any stagnant air spaces in your grow tent.
  6. Sounds like you have it hooked up wrong.

    The fan should be the last thing in the chain.

    It should be pulling air through the scrubber, not forcing it in.
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  7. I’ll be damned. That explains it all. Thank you for the simple, kind answer. Very much appreciated!
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