Carbon Filters

Carbon filters used in hydroponics play an essential part in scrubbing the air free of any unwanted odours leaving the growing area via the ventilation and extraction system. Carbon filters are attached in-line with the extraction system and effectively become part of it. Activated charcoal carbon granules absorb and clean the air, thereby eliminating such smells.

Carbon filters work by adsorption, a process by which any pollutants in the air are trapped within the porous structure of the carbon substrate used within the filter. This substrate is composed of many carbon granules, each highly porous. If you were to “unwrap” the active surface of this, you’d find it covered an extensive area where any contaminants will become trapped.

Activated carbon is used in such filters, having been treated to have a larger surface area than non-treated carbon. So much so that one gram of this activated carbon will have a surface area that is slightly larger than 32,000 square feet (3,000 square metres)!

Activated carbon filters are used broadly in the hydroponics sector to reduce or eliminate odours and control odorous emissions from growing rooms and tents. As the air passes through the existing in-line ventilation exhaust system, it is cleansed free from odours, spores, allergens, or anything dangerous or unpleasant.

This charcoal becomes “activated” when heat-treated at extremely high temperatures, which alters its actual structure. This chemical reaction, caused by the high temperature, results in the extensive surface area mentioned above and renders it much more porous than it would otherwise be.

Carbonaceous source materials, such as coconut husk, bamboo, wood, coco coir, willow peat, coal, lignite and petroleum pitch, produce Activated Carbon.

These carbon filters have many useful applications in hydroponic and soil-based horticulture. These include filtering mould spores, dust, pollen, insects, and their larvae from the air and vigorous scrubbing of odour and odour-bearing particulates from the exhausted air.

Change your carbon filters after 18 to 24 months of regular or constant use for best results. In some less demanding applications, they may last for anything up to three or four years. However, their lifecycle depends on their usage, the quality of carbon, humidity and plant species, among other considerations.

Carbon filters will, on balance, be able to remove more than 80 different chemicals and are very good at considerably reducing the incidence of a further 52 compounds, including harmful particulates such as lead. They can also deal with many known pathogens that float in the air. However, you should be aware that activated carbon filters cannot effectively eradicate microbial contaminants, including viruses and bacteria.

However, when used together, activated carbon and HEPA filters will be able to trap as much as 99.97% of small particulates greater than 0.3 microns. Beneficial for those who suffer allergies or are bothered by air that is impure, and this includes second-hand cigarette smoke.

The choice of a carbon filter is essential in that it needs to match the extractor in-line fan system as a prime consideration. You should make sure, in particular, that the volumes of air extracted are the same for the extractor fan and the filter, and the figures published for one should be the same as the figures published for the other. Above all, you’ll want to ensure that the filter you choose will enable the fan to reach its full potential and perform well enough to clean your expelled air to a very high standard.