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About Our Carbon Filters
A carbon filter is what keeps a grow space discreet. Air passes through a bed of activated carbon, which traps the odour molecules that growing vegetables, herbs and microgreens give off. The cleaned air then leaves the room with no smell. We stock the full Prima Klima line: the compact K2600 range and the deeper, longer-lasting K1600 range. Prices start at £40 for the K2600mini.
The K2600 filters are lighter and shorter, ideal for cabinets and small rooms. The K1600 filters hold more carbon, so they last longer and handle bigger airflows. Match the filter's optimal airflow and flange to your extractor fan. The K2600mini suits the G-tools mini fan; a K1604 pairs with a PK 125 EC-TC. Add an ECTC controller for hands-off speed control.
Why We Stock This Range
"The mistake people make is buying a filter on maximum airflow alone. What matters is the optimal figure, which is the speed where the air spends enough time in the carbon to actually get scrubbed. Push air through too fast and odour slips straight past. So I tell growers to size the filter on its optimal airflow, then choose a fan that runs at or below that. The K1600 range is what I reach for when someone wants a filter that lasts years rather than months."
— Matt, Founder of Greenhouse Stores💡 Tip: Size a carbon filter on its optimal airflow, never its maximum. The K2601 is rated 480 m3/hour maximum but works best at 360 m3/hour. Run your fan at that figure and odour control stays solid.
🔧 Matt's Setup Tip: Keep the filter dry
Activated carbon hates damp. High humidity clogs the pores and shortens the filter's life fast. Keep relative humidity under about 70%, and never let the filter sit on a wet floor. Mounted high in the warm air at the top of the space, it works best and lasts longest.
Carbon filters compared
| Filter | Optimal airflow | Height / Flange | From |
|---|---|---|---|
| K2600mini | 160 m3/hour | 250mm / 125mm | £40 |
| K2601 ⭐ Matt's Pick | 360 m3/hour | 400mm / 125mm | £55 |
| K1604 | 460 m3/hour | 600mm / 125mm | £130 |
| K2603 | 800 m3/hour | 650mm / 160mm | £133 |
| K1610 | 1150 m3/hour | 800mm / 200mm | £249 |
Frequently asked questions
How does a carbon filter remove odour?
Air passes through a bed of activated carbon, which traps odour molecules. The carbon's huge surface area grabs the smell, so the air leaving the room is clean. It works on growing plant odours, damp and general stale air alike.
What size carbon filter do I need?
Match the filter's optimal airflow to your fan. The K2600mini suits 160 m3/hour, the K2601 suits 360 m3/hour, and the K1610 handles 1150 m3/hour. Bigger rooms and bigger fans need a taller filter holding more carbon.
What is the difference between the K2600 and K1600 ranges?
The K2600 filters are shorter and lighter, made for cabinets and small rooms. The K1600 filters are deeper, hold more carbon, and last longer at higher airflows. Choose K1600 when you want a long service life.
How long does a carbon filter last?
Most run 18 to 24 months in normal use. Life depends on humidity, hours run, and how strong the odour is. Keeping the air below about 70% humidity protects the carbon and stretches its working life.
Does the filter flange need to match the fan?
Yes, the filter, fan and ducting must share one flange diameter. Our filters come in 125mm, 160mm and 200mm. Check your extractor fan outlet before ordering so everything clamps together cleanly.
Should the fan pull or push air through the filter?
Pulling air through the filter works best. It keeps the room under slight negative pressure, which stops odour escaping past door and seal gaps. Mount the filter high, where the warmest, most odour-laden air collects.
Need Help Choosing?
Call our team free on 0800 098 8877