Carbon Filters
3 min

A Closer Look At Carbon Filters And How To Make Your Own

3 min
Growing Seedshop

One of the most entrancing things about cannabis is it's unique aroma, but that wonderful smell has its pros and cons. Carbon Filters are one tool to help you fight the smell if need be. Learn more about them, and how to make your own at Zamnesia.

There are several types of carbon filters - find out which will work best for you.


That smell we all adore is indistinguishable and can get you in trouble if the wrong person catches a whiff. There are many ways to eliminate odours in a grow room and in this article, we'll be discussing carbon filters, also known as scrubbers. A carbon filter is one of the best tools available to control smells, regardless of the size of your garden.

Carbon filters are installed in a grow room's exhaust system, and it neutralises any odours in the air that passes through it. They're highly recommended to get rid of that strong smell.


How do Carbon Filters Work?

A carbon filter is essentially a giant tube filled with activated carbon. When air passes through the tube, the carbon neutralises any odours that are present and clean air is pushed back out.

It's imperative to make sure that the exhaust  system is set up correctly when using carbon filters. You will need a strong, inline fan to push the air through the filter. Otherwise, smells will leak both into and out of the room. If you neglect this detail, the whole system would be pretty useless.


There are two different types of carbon filters, granular and block. Granular filters are usually used for smaller gardens, while block filters are larger and able to handle the filtration needs of a larger cultivation area.

Choose your carbon filter based on how much air you need to purify. This is measured in cubic feet per minute (CFM) and your exhaust fan should have a CFM rating label on it somewhere. Your filter should have a CFM rating that's equal to or lower than the fan. This is to ensure the fan is strong enough to do its job and move air through the carbon filter.


If you're a do-it-yourself type, you'll be interested to know that you can make your own carbon filter for a fraction of the cost of buying one already assembled.


  • 1 Roll of Aluminium Screen or Chicken Wire
  • 1 PVC Adapter (with a 10-15cm diameter) 
  • 1 PVC Cleanout Cap (Cleanout Cap and PVC Adapter should have approximately the same diameter) 
  • 1 Roll of Duct Tape
  • 1 Roll of Quilt Batting 
  • 1 Dryer Vent Hose (suitable for fitting on the PVC Adapter)
  • A round hamper basket / laundry basket, preferably plastic and with lid
  • Activated Carbon (preferably pelletized activated carbon )



You can purchase activated carbon from a local aquarium shop or pet store. Pelletized activated carbons are typically more reliable than crushed carbons. Crushed carbons have less surface area which causes them to clog the filter and produce debris. Pelletized activated carbon is essentially just crushed carbon that was formed into a pellet and washed in an acid mixture. A 20l bucket of pelletized activated carbon usually lasts about 1 year.


Create a tube or cylinder shape (with a diameter to match your cleanout cap) out of aluminium screen, and plug one end with the PVC cleanout cap. Duct tape it into place.

Place the screen tube you have just made upright in the hamper basket, and trim it so that it is even with the height of the hamper. Precision is not of utmost important here; you can be 2-3cm short without problem.

Plug the other end of your screen tube with the adapter, and secure with duct tape.

Unroll the quilt batting and fold it in two, length-wise. Then, make sure the width of your doubled-over batting of is the same width as that of your screen tube. You most likely will need to trim it to fit.

Tape one end of the batting to the screen tube. Use just one piece of duct tape to keep the batting in place when rolling, as you would use a small piece of tape to secure wrapping paper when wrapping up a birthday gift.

Roll up the screen tube in the quilt batting, until the tube is covered all-around and the batting overlaps slightly. Trim and tape both ends with duct tape.

Now, use the same size of doubled-over quilt batting to line the inner sides of the hamper basket. Tape the top edges to keep it in place.

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Place the screen tube in the centre of the hamper (upright, with the cleanout cap on the bottom), and fill the space in between screen tube and hamper sides with the activated carbon. If you feel you are using too much carbon to fill up the empty space, thicken up the outside of the screen tube with more quilt batting. Keep in mind that a 26mm thick layer of carbon is considered to be optimal.

Add batting to the top to cover up the exposed carbon.

Cut the centre out of the hamper lid, so that the PVC adapter can stick upwards through the hole. Tape the hamper lid into place if you wish.

Attach the dryer hose to the PVC adapter, attach the other end to the output of an air blower and presto! One very cheap and functional Carbon Air Filter, at your service!

If well taken care of, carbon filters can last a very long time and will completely eradicate any odours from your grow room. They're very easy to maintain and extremely reliable, which is why they are one of the most popular ventilation choices for seasoned growers.


Written by: Zamnesia
Zamnesia has spent years honing its products, ranges, and knowledge of all things psychedelic. Driven by the spirit of Zammi, Zamnesia strives to bring you accurate, factual, and informative content.

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