Activated carbon

has been used in home aquariums for decades, and it is still the largest selling filtration media product. As new types of filters and media have become available, the debate has raged over the value of using activated carbon in filters. Some believe it should be used as a standard media for continuous use in most filters. Others feel it should only be used in for special needs, and still others believe that activated carbon should no longer be used at all.

What Is Activated Carbon?

Activated carbon is made from carbonaceous material that has been heat treated at very high temperatures to create many tiny pores, greatly increasing its surface area. These tiny pores and massive surface area allow the filter media to trap a large volume of material, making it useful for removing pollutants from both air and water. Different methods of creating activated carbon result in different forms of the material suitable for different uses. In aquariums, the form mostly used is GAC, or granular activated carbon. Forms of activated carbon include:

Placement in Filter

Activated carbon will lose its effectiveness rather quickly if exposed to lots of debris from the aquarium. Therefore, carbon should be placed after the mechanical filtration media in the filter. Keep in mind that if you do not keep your tank clean, and debris builds up in the filter, the activated carbon will not be effective.