There is always a puff of odor that makes it through the carbon filter at lights off

Indoor Growing
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I’ve brought this up on other forums in the past, so I’ll bring it here and see if there is any new insight about this…

I’ve been growing indoors for over two decades now, and I can say that this has always been a thing. I’ve tried changing things out over the years, experimented with a few hypotheses, and I’ve never been able to prevent this puff of odor from occurring. It’s so much like clockwork, literally, that I can always know when the lights just turned off because I’ll smell that sweet smell all throughout the house for a few brief minutes before it disappears and doesn’t come back for another 24 hours or so.

To this day, I don’t know what causes it. I also never see anyone mention it, which is confusing to me since it’s a real thing. My primary guess is that when plants detect that night time has come, they must release a large amount of moisture that overwhelms the carbon filter for a few minutes. But this is just my guess.

Does anyone want to talk about this? Have you experienced it? If not, why is this such an ever-present circumstance for me, in my gardens? Again, I’ve been doing this for twenty-something years and it’s always been a thing since I first started using carbon filters. In the beginning I thought it was something I was doing, or bad carbon or something… But now I just accept it and make sure my timer never shuts off when I would be having visitors.

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I have experianced that when the RH goes ape shit, over 70+% the carbon scrubber looses effect. Not all, but it’s not nearly as effective.

But if it’s a case of damp carbon, it wouldn’t just last for a minute and go away again.
Would take a bit to dry out the carbon

Do you have any fan’s running on timers, so you might loose the negative pressure in your grow area for a few min or something?

Also just gone back to industrial filters, after trying an Eco Carbon scrubber.
What type of scrubber do you use, if your grow area is running under negative pressure 24/7?

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There’s never any loss in negative pressure. I don’t use any separate fans other than the one that’s changing the air in any given tent, and they all always stay on 24/7.

In my experience, carbon filters work extremely well… for around 23 hours and 56 minutes a day or so. It’s very weird to me, but it’s been such a constant all along that I know there is a reason for it. I just haven’t figured out what it is. It happens on every brand filter. Expensive and knock-off. It’s a phenomenon that happens at lights-out, every single day, in every garden I’ve ever had: lights go out, concentrated puff of aroma leaks out of the tent, and I can detect it, faintly, for about 3 or 4 minutes.

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that’s what I was going to say - they stop working when humidity goes up. It’s not permanent though, they start working again when it drops

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Sounds odd, but again my scrubber exhaust directly outside.
So I wouldn’t notice a 5 min leak of smelly air, and never grown in tents venting into the house.

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Maybe try turning off lights in stages or dimming before turning off, to mimic sunset so humidity comes on slower.

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Maybe it’s the time of day your neighbour steps out for a quick bowl :joy::joy:

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Dang, am I the only one this happens to? :smile:

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At the moment I have some pretty big lights in my 2x2x4 tents, it’s always 95°-98° F at the top of my tent. That should dry out any carbon.
When the lights are on that is.
So this does make sense why this happens to me also.
I need to rig up a timed exterior fan, one that runs only at lights out.
Running an exterior fan 24/7 makes a big dent in my heating / cooling budget.
It’s gotta have a negative back pressure flap, or just a timed, motorized damper, assume the fan(s) will be on 24/7…
I just switched my grow to 11/13 young plants so not much smell, yet.
Suggestions?

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Is there any benefit, besides smell reduction, in having a carbon scrubber