ON OUR SHELF · THE FAN AND FILTER BAYS
A tent holds its numbers when the air keeps moving.
Our fan and filter bays hold inline fans, carbon filters, ducting, clip fans and the controllers that run them, and the tents they go in are on the shelf beside them. Here is how to size a fan to your tent, where the fresh air comes in, and how to set the controller so the tent holds its lanes.
How we stock it at Green Zone
The fan and filter bays hold AC Infinity Cloudline fans and controllers, Can-Lite and AC Infinity carbon filters, ducting, clip fans and dehumidifiers. Tents from Gorilla Grow Tent and Secret Jardin are on the tent shelf. Almost everything is boxed, so bring the inside size of your tent and the duct size of anything you already own.
Most airflow trouble we see isn't a bad fan. It's a fan picked for the tent without counting the filter and duct, a tent with no way for fresh air to get in, or a clip fan aimed straight at the plants.
Exhaust, intake and circulation, in one paragraph
A tent needs three kinds of air movement. Exhaust: an inline fan, set as high as it can go, pulls warm, wet air out through a carbon filter, which keeps the smell in the tent. Intake: fresh air comes in low to replace it, usually through an open port. Circulation: a clip fan inside keeps air moving above and below the canopy. A controller ties it together, speeding the exhaust up when the tent gets warm or humid and back down when it settles.
The lineup
Gorilla Grow Tent Pro (3 by 3, 4 by 4, 5 by 5)
1680D canvas on a steel frame rated for a 300 lb hanging load, so fans, filters and lights hang without flex. Six 11 inch double-cinching duct ports, with mesh pre-filters on the lower vents. It comes with a 1 ft extension, and a 2 ft kit takes it to 8 ft 11 in. Gorilla suggests a 6 inch inline fan plus a carbon filter for the 4 by 4. Gorilla used to sell this line as the Original.
Where it fits: Tall tents, with room to add height
Gorilla Grow Tent Shorty (3 by 3 and 4 by 8)
4 ft 11 in tall, or 5 ft 8 in with the 9 inch extension in the box, in the same 1680D fabric. The 3 by 3 has three 11 inch and two 9 inch duct ports; the 4 by 8 has four of each. Gorilla no longer lists the Shorty, so what's on our shelf is what there is.
Where it fits: Basements, attics and low ceilings
Secret Jardin Dark Room DR150
150 by 150 by 217 cm (5 ft by 5 ft by 85 inches), 400D Mylar canvas on 25 mm stainless poles, with a double-flap zip Secret Jardin calls 100% lightproof. Its duct flanges take connectors from 150 to 250 mm. Secret Jardin says its tents are airtight, so leave an air intake open whenever the extraction runs.
Where it fits: A 5 by 5 that seals tight
AC Infinity Cloudline T4 and T8
Inline mixed-flow fans with a quiet EC motor: the T4 moves 226 CFM at 26 dBA and the T8 857 CFM at 38 dBA. Each comes with a Controller 69 Pro that speeds the fan up on temperature, humidity or VPD triggers, holds a minimum speed in between, and runs timers and schedules from the app.
Where it fits: Exhaust, with the controller in the box
AC Infinity Cloudline S4 and S8
The same airflow as the T4 and T8, with a wired 10-speed controller instead of the smart one, and memory that keeps the last speed after a power cut. Add any AC Infinity UIS controller later for triggers. Our S8 box says Cloudline PRO S8; AC Infinity now sells it as the S8.
Where it fits: Exhaust, set by hand
AC Infinity Controller 69 Pro and Pro+
A 12-foot sensor probe reads temperature and humidity, and the controller works the fans and other devices on temperature, humidity and VPD. The Pro runs up to four devices and the Pro+ up to eight, each with its own program: triggers, minimum levels, schedules and timers, by Bluetooth or Wi-Fi. AC Infinity lists Cloudline fans and Cloudforge humidifiers among what it runs.
Where it fits: One sensor running the tent
Can-Lite carbon filters
100% Australian granulated carbon in a 2 inch bed, assembled in Vancouver, Washington. The CFM on the box is the most the filter takes recirculating air in a room. For exhaust, Can-Filters rates it at about half: the 12 by 40 says 1800 CFM on the box and 750 to 900 for exhaust, and Can-Filters says not to go over the exhaust rating.
Where it fits: Odor control, matched to the fan
AC Infinity carbon filter, 4 inch
Australian RC412 charcoal in a 38 mm bed, rated 210 CFM, for exhaust or intake. The flanges reverse to stretch its life, and it comes with two machine-washable pre-filter cloths.
Where it fits: Small tents on a 4 inch fan
Pre-filter sleeves (Can-Lite and AC Infinity)
A sleeve over the filter that stops dust, hair, lint and pollen before they reach the carbon. Can-Filters says to replace the pre-filter when it gets dirty, because a dirty one cuts the airflow through the filter. AC Infinity's cloth is washable and reusable for up to 6 months of continuous use between cleanings.
Where it fits: Keeping dust out of the carbon
Ducting: Max-Duct and Active Air
Max-Duct is triple foil laminate in white PVC with UV inhibitors; Active Air Premium is 3-ply aluminum foil laminate on a helix wire. Both come in 25 ft rolls with two clamps. AC Infinity and Can-Filters both say duct length and bends cost airflow, so keep runs short.
Where it fits: Fan to filter to the outside
Spider Farmer 6 inch clip fan
A grip-clip fan with an EC motor, 10 speeds and 10 levels of oscillation, rated IP54. Spider Farmer says to set it so air moves both above and beneath the canopy, and not to blast the plants with a strong fan.
Where it fits: Air moving above and below the canopy
Hurricane Pro wall fans, 16 and 20 inch
All-metal oscillating wall fans with 3 speeds and adjustable tilt: the 16 inch moves 2400 CFM on high and the 20 inch 4500 CFM. The motor is thermally protected and shuts off before it overheats.
Where it fits: Grow rooms, and the room around the tent
Ideal-Air 50 pint dehumidifier
Rated at 50 pints a day under the AHAM test (80°F, 60% RH). It shuts off when its 6 liter tank is full, can be plumbed to a drain to run without emptying, and its filter comes out to wash.
Where it fits: A tent or room that runs too wet
AC Infinity Cloudforge T7 humidifier
An ultrasonic humidifier with a 15 liter tank, up to 1300 ml an hour and up to 30 hours of runtime, and an automatic valve that refills it from a water line. It has its own VPD and humidity triggers, and the Controller 69 Pro can run it. Below about 40% RH is too dry for most grows.
Where it fits: A tent that runs too dry
Also in the bays: Can-Fan and Hyper Fan inline fans, Phat filters, Can-Duct, Titan Controls controllers and a Hurricane 30 inch drum fan. Ask at the counter for sizes.
Size the fan: the 1 to 3 minute rule
Work out the tent's volume in cubic feet: length × width × height. Replace that air every 1 to 3 minutes. A 4 by 4 tent 7 feet tall holds 112 cubic feet, so that's about 37 to 112 CFM of air leaving the tent. The makers sit at the two ends of that lane: Can-Filters sizes exhaust at length × width × height ÷ 3, and AC Infinity at one full exchange a minute.
A fan's rated CFM is what it moves with nothing in the way. AC Infinity's own guide adds about 60% for a carbon filter, about 20% for ducting and up to 50% for LED heat, says those percentages vary, and recommends a fan with speed control and 25% or more headroom. That's why we size up and turn it down with the controller. Leave an intake 3 to 4 times the exhaust opening, and with the fan on, the walls should bow in slightly. Those are rules of thumb. The check that counts is the tent's temperature and RH.
How it fits your grow, in 3 steps
Step 1. Size the exhaust to the tent, then match the filter.
Volume first, then add for the filter, duct and light, and buy a fan with speed control. Mount it as high as you can. Pick a carbon filter whose exhaust rating covers the airflow you'll run; Can-Filters says not to go over it.
Step 2. Let fresh air in low, and keep it moving inside.
Leave an intake 3 to 4 times the exhaust opening and look for walls that bow in slightly. Hang a clip fan so air moves above and under the canopy, never blasting one plant. Put the temperature and humidity sensor at canopy height, shaded and out of the fan blast.
Step 3. Set the controller to the lane, then move one thing at a time.
In veg, steer the canopy toward 75 to 82°F and 55 to 70% RH; in flower, 72 to 80°F, with RH at 45 to 60% early and 40 to 50% late. Give a dehumidifier a wide band, on near 58% and off near 52%, not a fixed 50%. Move RH 3 to 5 points or temperature about 2°F at a time, never both, then give it at least an hour and judge it across a full day and night.
Who it's for, and who it's not for
A good fit if
You grow in a tent or a closet, and the temperature or humidity swings when the lights change.
The smell has to stay in the tent.
You're setting up a first tent and want the fan, filter, duct and tent to fit each other.
Not the right fit if
You grow houseplants on a shelf in the house. This page is about closed tents; start at /in-store/houseplants.
The whole room runs too wet or too hot before a tent goes in. Start with the room: What humidity should I run, and what if I can't hit it?.
Common mistakes we help people avoid
Picking the fan by the tent alone. A carbon filter, ducting and LED heat all raise the airflow you need, and AC Infinity recommends 25% or more headroom with speed control.
Reading the Can-Lite box as the exhaust rating. The box number is the recirculation maximum; the exhaust rating is about half.
Sealing the tent. With no intake, the fan pulls the walls in hard. Secret Jardin says to leave an air intake open so the tent doesn't implode. Walls that bow in slightly are the goal.
Aiming the clip fan straight at the plants. Spider Farmer says too much wind can harm leaves and stems; move air above and under the canopy instead.
Hanging the sensor in the fan's blast. It reads the fan, not the canopy. Keep it at canopy height, shaded, away from walls and the dehumidifier exhaust.
Running the filter in very wet air for days. Can-Filters says not to run a filter for long periods at or above 70% humidity.
Chasing temperature and humidity at once. One change, one knob, then wait.
Frequently asked questions
What size inline fan does my tent need?
Start with the tent's volume and replace it every 1 to 3 minutes. Then count the filter, duct and light, and buy a fan with speed control and some headroom. Gorilla suggests a 6 inch inline fan with a carbon filter for its 4 by 4. Bring the inside size of your tent and we'll match one.
Should the intake be a fan, or just an open port?
An open port low on the tent works for most tents: about 3 to 4 times the exhaust opening, with walls that bow in slightly when the fan runs. Gorilla's lower vents have mesh pre-filters to keep critters out.
My tent walls suck in. Is that bad?
A slight bow inward means the exhaust is working. If they pull in hard, open more intake or turn the fan down. Gorilla sells a High CFM kit because strong exhaust fans can pull its canvas walls in.
Why does the humidity jump when the lights go off?
A rise of 15 to 20 points at lights-off is normal, and it settles over the dark period. In late flower, act when RH holds in the high 60s or above for hours, or anything turns wet. A short spike is not the risk.
How often do I clean or change the pre-filter?
Can-Filters says to replace it when it gets dirty, because a dirty pre-filter cuts airflow through the filter. AC Infinity's cloth is washable, and reusable for up to 6 months of continuous use between cleanings.
Can one controller run my fan and humidifier?
The AC Infinity Controller 69 Pro runs up to four devices and the Pro+ up to eight, including Cloudline fans and Cloudforge humidifiers.
Do you carry every size?
Not every fan, filter or tent size is out at once. Call (508) 459-9609 to check before you drive.
Keep going
Departments: Climate, air & controls · Grow tents · Lighting
Grower answers: What humidity should I run, and what if I can't hit it? · Tacoing or bleached tops: is it light or heat?
More deep dives: Pest plan: what we reach for first · pH and EC meters · Which soil bag? The soil room compared
Want the short version of how we keep a grow steady? Get the free Stability Playbook
Before you drive
In the fan and filter bays: AC Infinity, Can-Fan and Hyper Fan inline fans; Can-Lite, AC Infinity and Phat carbon filters; Max-Duct, Can-Duct and Active Air ducting; AC Infinity and Titan Controls controllers; Hurricane wall and drum fans; Ideal-Air and Eva-Dry dehumidifiers.
On the tent shelf: Gorilla Grow Tent (Pro, Shorty and Lite) and Secret Jardin (Dark Room, Dark Street and OneDeal).
Bring your tent's inside size, its height with any extension, and the duct size of what you already own.
Need one exact fan, filter or tent? Call (508) 459-9609 first.
Photographed in the store on October 9 and October 15, 2026.