A carbon filter is what stops a grow room from smelling like a grow room. Air is pulled through a bed of activated charcoal, the charcoal adsorbs the odour molecules, and the air leaving the duct is close to neutral. Canada Grow Supplies stocks inline carbon filters, pre-filters and complete fan-and-filter kits from AC Infinity, Vortex and Stealth Filtration, plus replacement cartridges for Anden, Athena, Aguair and Growonix equipment. Orders of $149 or more of eligible items ship free within Canada.
What size carbon filter do I need?
Size the fan first, then match the filter to it. Work out the volume of your space in cubic feet (length x width x height) and choose a fan that can move that volume in roughly one to three minutes, then add about 25% because the filter and ducting cost you airflow.
- A 2x4x5 ft tent is about 40 cubic feet, so roughly 50 CFM once you allow for the filter.
- A 4x4x6.5 ft tent is about 104 cubic feet, so roughly 130 CFM.
- A 5x5x6.5 ft tent is about 162 cubic feet, so roughly 200 CFM.
Then pick a filter rated at or just above the fan. Our AC Infinity refillable kits are rated 210 CFM at 4 inches, 410 CFM at 6 inches and 770 CFM at 8 inches. Match the flange to the duct as well: a 6-inch fan wants a 6-inch filter, and reducers cost you airflow you have just paid for.
Which way round does the filter go?
Both directions work. The common setup is to hang the filter inside the tent with the fan after it, so the fan pulls air through the charcoal and pushes it out of the duct. This keeps the fan quieter and keeps the ducting under negative pressure, so any leak pulls air in rather than letting unfiltered air out. Mounting the filter on the outside after the fan also works, but every joint before the filter has to be sealed or smell escapes there.
How long does a carbon filter last?
Manufacturers generally rate a sealed grow-room carbon filter at somewhere between 12 and 24 months of continuous use. What shortens it is dust and moisture rather than hours: charcoal that stays damp loses capacity, and a filter clogged with lint is starved of airflow. The pre-filter is the part you service often; the charcoal itself is not. The practical test is simple, and it is the only one that matters: when you can smell the room again, the filter is spent.
Does humidity affect a carbon filter?
Yes. Activated charcoal adsorbs water as readily as it adsorbs odour, so in persistently humid air some of its capacity is taken up by moisture and it captures less of what you wanted it to capture. Running your space in the normal range for healthy plants is enough; what does real damage is storing a filter in a damp basement or garage between grows, or running one in air that sits near saturation for weeks.
Refillable filters and pre-filters
If you run year-round, a refillable filter is worth the up-front cost: when the charcoal is spent you replace the charcoal, not the whole housing. We stock the AC Infinity Refillable Carbon Filter Kit with charcoal refills, and the AC Infinity Duct Carbon Filter XL, which is packed with Australian charcoal.
The pre-filter is the cheap part that protects the expensive part. It is a cloth sleeve that catches dust and lint before they reach the charcoal, and washing or replacing it is the single easiest way to get the full life out of a filter. We carry pre-filters for AC Infinity, Vortex and Stealth Filtration housings.
Fan and filter kits
Starting from nothing, a kit saves you matching parts. The AC Infinity Air Filtration Kit Pro pairs an inline fan and smart controller with a carbon filter and ducting in 4, 6 and 8 inch sizes, already sized to work together.
Replacement cartridges for other equipment
Not everything here is an odour filter. This collection also holds replacement cartridges for gear you may already own: Anden dehumidifier filters (A70, A95, A95F and A130), Athena filters for the Culture Kit, the Aguair ClensAir yearly maintenance kit, and the Growonix CF-2520 coconut carbon cartridge, which is a water filter rather than an air filter.
Shipping across Canada
Orders of $149 or more of eligible items ship free within Canada; oversized items and remote destinations carry a handling fee, and every order goes out in discreet packaging with no labels on the box. Not sure which filter suits your fan? Call us at 888-349-0321.
