Granular activated carbon is a well-established filtration technology, used for the reduction of a wide range of contaminants in tap water. It is extremely effective in the reduction of volatile organic compounds which are harmful to the reef aquarium and can cause permanent damage to your RO membrane if allowed to pass through.

With its incredibly high surface area, granular activated carbon is highly efficient as an absorption media. It is very effective at treating tap water with high levels of chlorine and chloramine, doing a lot of the heavy lifting when used in conjunction with a carbon block filter.