Complete guide on how to eliminate odors with activated carbon filters , we will understand together their operation and assembly with their main characteristics. We will explain the important role they have and why to use an activated carbon filter in our indoor grow tents.

What are activeted carbon filters for grow room and HOW do they WORK?

In general, in the process of eliminating odors coming from cultivation environments, like any other domestic environment such as the kitchen or bathroom but also from work environments, the protagonists are activated carbon filters. 

The activated carbon filter is a device that is part of the air treatment and recirculation system, and is a fundamental element for all growers who want to tackle indoor cultivation. The main feature of an activated carbon filter is to capture the terpene molecules, responsible for the intense fragrances that plants give off during their growth and floral maturation, via a barrier made up of activated carbon granules of various sizes.

Activated carbons derive from raw materials, treated with specific industrial processes, which have a high carbon content and can have a vegetal origin such as the shells of some nuts (generally coconut and almonds), or an animal origin such as bones. The main characteristic of these carbons is their very high porosity. 

To get a clear idea, if we were able to measure the surface area of ​​the pores present in a gram of activated carbon, it would cover a football field.
This particular characteristic means that any fluid that passes through a barrier of activated carbon would be microfiltered and elements, such as the terpene molecules present in the air, remain trapped in these pores.

In indoor growing, the process of eliminating odors with activated carbon filters is carried out by means of a device, generally tubular in shape, which is installed inside the grow tent and is connected to the air extractor via special flanges or flexible hoses.

Its installation absolutely does not compromise the correct functioning of the extractor, indeed the manufacturers take into account the possible installation of these filters considering a minimum reduction in the flow rate of the air extractor.

The activated carbon filter works as a barrier against terpene molecules, which are stored inside the pores of the carbons, the air is purified and conveyed towards the outside of the grow room by the extractor. The outgoing air is purified and odor-free, which is a fundamental condition if we want to continue our cultivation of cannabis in indoors in grow tents in safety.

Usually an activated carbon filter consists of:

  • A first filtering layer made up of fabric, generally cotton, which acts as the first filtering barrier, trapping dust and substrate residues possibly put into circulation by the internal ventilation.
  • A double metal cage which has a mesh of such size as to keep the activated carbon granules compact between the two cages.
  • Obviously the layer between the two cages is made up of activated carbon granules, the main part of the filter.
  • The innermost part is hollow and from here the air, already purified by the granules, is conveyed and expelled outside by the air extractor.
  • Finally, a connection flange connects the filter directly to the extractor or, in particular needs or system setups, we can connect them with flexible air intake hoses that connect the filter to the extractor - aspirator.

When fitting an activated carbon filter is recommended

Is it always recommended to install an activated carbon filter? If so, when should I fit an activated carbon filter?
If we are wondering whether an activated carbon filter is useful for the correct development of the plant or whether I can even do without it, know that the answer is no! We strongly advise against tackling indoor cultivation without an adequate anti-odor filter . 

In indoor growing, the activated carbon filter is an essential element for our safety and that of those who live with us, particularly in the most common situations where, for reasons of space or discretion in the case of cohabitation with other people, we assemble our grow tent inside the room we live in. 

At most, if we are in a hurry to start our cycle and we don't have one, we must mount the filter on the extractor by the beginning of the flowering phase. Although most Cannabis strains, especially when we have multiple specimens in our grow room, give off their characteristic odor after the first few weeks of vegetative growth.

True, an activated carbon filter mounted on the air extractor does not directly influence the growth and maturation of our plants even if, a top system and many expert growers choose to apply an activated carbon filter also at the air inlet to the interior of the grow room. 

In this case the application of the filter greatly influences the organoleptic characteristics of the final product such as aroma and flavour, purifying the incoming air from external odors but also dust and above all the many hateful hairs that we find inside our tops if we have our beloved four-legged friends at home.

How to correctly install an activated carbon filter

To correctly reduce the odors coming from our cultivation in the grow tent, our anti-odor filter must be positioned in a certain way. 

The normal practice on how to correctly install an activated carbon filter see the device always installed before the air extractor, in the upper part of the grow room or in any case above the plants, for correct odor capture. Therefore always inside the grow room, always before the air extractor which in turn can be located inside or outside the grow tent. 

If the air extraction device is located inside the tent, we can connect the filter directly to the inlet mouth of the aspirator with the appropriate flanges or fittings or, if the aspirator - extractors are located due to space or choice of setup outside the box, we can use a stretch of flexible aluminum tube to connect the filter to the extractor mouth.

However, in this case, special reflectors are used such as the cooled ones of the type: Airontek cooled reflector , Xtracool reflector or a Cooltube reflector; with these types of reflective screens the activated carbon filter must be mounted with the following setup:

  • first, the anti-odor filter connected to the reflector, again by means of special connection flanges;
  • the cooled reflector;
  • then our air extractor connected directly to the reflector or always with a stretch of flexible hose in case of external position of the extractor.

We must keep in mind that the life of activated carbon filters has a limit, after a maximum use which can range from 3 to 4 cycles the carbons become saturated and no longer guarantee a correct barrier against odors coming from cultivation. 

There are filters on the market for every need, even if you already own an air extractor, you can easily find the filter with the size you need or there are flanges that connect different sizes. So remember to change the filters, they are not eternal.

Types of activeted carbon fiters for grow tents

NOTE : it is necessary to inform you that activated carbon filters are not supported by air extractors of the VK0-100 and VK01-125 type.

  • 100mm activated carbon filter , flow rate 250m 3 /h for 40x40x120/140cm GrowBox
  • 125mm activated carbon filter, flow rate 250m 3 /h for GrowBox from 60x60x140/160cm to 80x80x160/180cm
  • 125mm activated carbon filter, flow rate 480m 3 /h for GrowBox from 80x80x160/180cm to 100x100x200cm
  • 150mm activated carbon filter, flow rate 600m 3 /h for GrowBox from 100x100x200cm to 120x120x200cm
  • 150mm activated carbon filter, flow rate 700m 3 /h for GrowBox from 120x120x200cm to 140x140x200cm
  • activated carbon filter 200mm, flow rate 1000m 3 /h for GrowBox from 140x140x200cm to 240x120x200cm
  • 250mm activated carbon filter, flow rate up to 1400m 3 /h for GrowBoxes from 240x120x200cm and larger

Are DIY carbon filters usefull for grow tents?

There are many tutorials online, both videos and detailed explanations for building your own do-it-yourself activated carbon filters , as well as self-generating commercial filters by purchasing only the activated carbon granules.

But is it really worth building an anti-odor filter with our own hands? Absolutely no! We strongly advise against manufacturing and assembling the activated carbon filter by yourself .

First of all, buying a lot of activated carbon granules alone still has a cost, then when dismantling the filter to replace the granules we can inevitably damage the filter and invalidate its correct functioning, finding ourselves having to buy a new filter in any case. However, if we even choose the path of self-building the carbon filter from scratch, in addition to having to incur expenses and waste time finding the materials, there is a real possibility of damaging or compromising the flow rate of our air extractor. 

The activated carbon filters on the market are already prepared and calibrated to guarantee correct air flow of the extractor, also taking into account the cubic meters of grow box available.

So why risk damaging the system or compromising correct odor filtering? With a few tens of euros we can purchase one or a set of filters suitable for our every need.