Carbon Filter lagging as plants flower

:grimacing: I have 7 flowering plants, maybe 100 buds & the house is begining to smell.
Is the filter full or csn it only cope with a certain amount of scent?
The filter is running 24/7 for about 3 months, going to break out the air freshener.
There is only about 3 weeks left to harvest.

filters don’t give signs when they fail usually it is good one day and toast the next think of it as a hole in an hour glass when they fail the hole gets bigger every minute, however it could be your exchange rate isn’t fast enough your plants will produce far more scent as they get closer to harvest. You wouldn’t have noticed during veg and early flower they produce less smell, The issue could be air leaks in your room too slow exchange rate not enough negative pressure to keep smell contained and pulled through filter or too small filter? if it is noticeable now when you harvest and dry it will be more so.

Thanks for the comment, filter still working, heaps of vaccuum and flow.
I just assumed if all the flow is from the intake ducts (2 fresh & 1 through the light) the filter, should cope with the scent.
My understanding is that the carbon filter the size that I have, should handle a 2 x 2 x 2M room. If it filters atomic particals why would some escape?

Either you have a leak somewhere in the ducting that runs from the filter to the exhaust that is allowing air into the vent line after the filter or your negative air pressure isn’t strong enough. The other could be your prefilter on the carbon filter is dirty and preventing it from fully pulling air.
The last could be from when you are entering your grow space the smell will escape into the area and disperse into other areas of the house from there. The more often you open it up the stronger and longer the smell will persist.

On a side note filters work best when pulling air through them inside the tent.

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this explains why I myself will not be getting a filter…I will be checking so often as to negate any filtered effect.
no filter until my wife complains, at least!

I only use a filter because I vent outside. It can smell up inside all it wants :slightly_smiling:

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lol JTheH has it right I did notice in the picture that you seem to be pushing air through filter or it is not in your tent with the plants if it is sucking it will pull the smell out of tent some of which may escape

I cant see the difference if its in or out of the tent, the fan determines the flow rate, the only difference is that its blowing rather than sucking.
I prefer to keep the motor heat from the fan outside the tent. In Australia its around 30 deg C

Your filters should be hooked up on the outtake not the intake.
On the Intake the filter isn’t doing its job.
Put them on the ou’t-take…proplem solved.
Seems to me someoe else was doing the same thing…


pushing air or pulling air, placement of fan is important.
you pull air out of a tent for air circulation…
you push air though an air cooled light…
you pull air through a filter…

Love that one, if my venting was hooked up like that the whole suburb would be sniffing around. but im sure it happens:smile:
Im sucking out from the tent pushing through the filter, I have 2 intakes from outside 1 goes through the light

I put mine up through the heating vents in my ceiling heat and smell. Then if your really about it then you could pit air freshener up there time release.


It is true you want the fan sucking through the filter. Those filters have a dust covering because they are intended to have the air flow go through them in that direction, where the dust cover would “pre-filter” the large dust particulates before the rest of the air goes through the activated carbon inside the metal housing. This might be a contributor to why the filter seems to not be working as well as it should. Also high humidity lessens the effectiveness of carbon filters.


Hi Mac,

See room design, cant figure any other option

Here is an example of how they are usually setup:

Theoretically the air running through the light shouldn’t pick up any smell and can be on it’s own vent system.

If you want to run only one exhaust fan and if you are cleaning the air anyway, it is actually better for the light to clean the air before it goes through the light hood, and so it would be filter to fan to light to duct and out of tent.

This shouldn’t really add much heat to the tent, you will be blowing it with the hot air from the light mostly out the tent. This will still run the tent at a negative pressure and it should still suck the air in at the vents/ducts at the bottom intake to the tent.



Hey Mac, looky what I just ordered

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Wow I would’ve just smoked my harvest to see how it turned out myself even passed a bit around to buddies for feedback seems like overkill unless you plan on breeding

Hi Don,

Im about to embark on a frio around Australia in a 4WD with camper, we will be camping in remote areas so I will need to test food & water,
I may offer the test service to smokers/growers for a small fee.
I can also measure the THC /CBD ect, to tell me when to harvest, should be more accurate then spying on trichromes


Trip around :blue_car: