RAM Carbon Filters – Full Range 4" to 12" (LITE, Pro, MIDI, HEAVY)

Here's an odd truth about smell: you stop noticing your own. Ten minutes in a room and your nose quietly files the odour under "normal". Your visitors, your neighbours and whoever shares the landing get no such grace period. A carbon filter is the polite fix. It cleans the air on its way out, so the only people who know what you're growing, brewing or drying are the ones you tell.

Most shops sell you a RAM filter. This listing carries the whole RAM range: all 19 sizes across four ranges, from a 4" cupboard filter to a 12" metre-plus monster. That means you can match the filter to your fan and your budget, instead of settling for whichever size happens to be in stock. RAM (Rapid Air Movement) is designed in the UK and is one of the best-known names in grow-room ventilation.

Which RAM range is yours?

The short version: small tent and a tight budget, pick LITE. Want proven RC412 carbon in almost any size, pick Pro. Strong fan or a big space, pick MIDI or HEAVY.

Why the carbon matters more than the can

Every carbon filter looks roughly the same from outside: a metal tube in a fabric sock. The difference is what's packed inside and how tightly. Loose carbon leaves gaps, and air, being lazy, takes the gap. Every RAM range is built around stopping that.

• RAM Pro: virgin Australian RC412 activated carbon. It's low in ash (under 13%) and granulated, so it packs tight with no easy shortcuts for odour. Its very fine pores (around 0.02 micron) give smells an enormous surface to stick to. RAM dries the carbon inline before compacting it, and expansion foam at the neck keeps the bed tight as it settles.
• AirTECH MIDI and HEAVY: premium Australian activated carbon, machine-packed into a deep bed (50mm on MIDI, 60mm on HEAVY) between concentric cylinders of perforated Zintec steel with 55% open area. An Acoustafoam expanding ring holds the compaction for the life of the filter, and the zinc-coated Zintec body and end caps shrug off knocks.
• AirTECH LITE: RAM's lightweight tent range. It's compact and affordable, with more airflow per pound than you'd expect.

MIDI, HEAVY and Pro filters come with a washable pre-filter sleeve. Dust is the quiet killer of carbon filters, because it clogs the pores before odour ever reaches them. The sleeve catches it first, and you just wash it.

Not just for growers

A carbon filter does one job: it takes smell out of moving air. That turns out to be useful in more places than you'd think:

• Grow tents for herbs, chillies, tomatoes and flowering houseplants
• Mushroom fruiting chambers, which have a surprisingly earthy aroma
• Drying rooms for herbs, chillies and flowers
• Fermentation and home-brew corners
• Hobby rooms with paint, glue or resin smells (for odour only; a carbon filter is not a substitute for proper fume extraction or a respirator)

Rose's Pro-Tip

"Pull, don't push. Mount the filter inside your tent or room and have the fan draw air through it, so the whole space sits under slight negative pressure. That way any air leaking out of a gap or a zip is leaking in, not out. And size up: a filter rated about 20% above your fan's free-flow figure lasts noticeably longer, because it never has to work flat out. If two filters share a duct size, the longer one holds more carbon and will outlast the shorter one."

How to match a filter to your fan

Start with diameter. It's simplest when fan, filter and ducting all share one size. If they differ, go for a filter slightly larger than the fan rather than smaller. Ducting and the filter itself add resistance, so your fan will move less air in real life than its free-flow rating says. Choose a filter rated about 20% above the fan's free-flow rate, and remember that every filter works better and lasts longer when the real airflow sits below its maximum.

Full specifications

MIDI carbon bed: 50mm. HEAVY carbon bed: 60mm. AirTECH mesh: perforated Zintec, 55% open area.

FAQ

LITE, Pro, MIDI or HEAVY: what's the real difference?
Mostly how much carbon you get and how hard the filter can be pushed. LITE is the light, affordable tent option. Pro is the proven all-rounder with RC412 carbon. MIDI and HEAVY have the deepest carbon beds and the highest airflow ratings, so they suit powerful fans and big spaces, and they last the longest when run below their maximum.

How long does a carbon filter last?
It depends on how hard it works, how humid the air is and how much dust gets in. Carbon filters work best below about 80% humidity. Keep the pre-filter sleeve clean and don't run the filter beyond its rating, and it will last far longer. When you start noticing smell with the fan running as normal, it's time for a new one.

Can I use it to bring air in rather than out?
Yes. Mounted on the intake side, it will clean incoming air. But its main job, and where it shines, is scrubbing air on the way out.

Does it need a fan?
Yes. A carbon filter is passive. It needs an inline fan of the same (or slightly smaller) duct size to pull air through it.

How do I hang the big ones?
The 10" and 12" filters are heavy. Hang them from a filter stand or strong ceiling hooks and chains, never from the ducting or the fan.