Red Sea REEF-SPEC Carbon 2000ml. Red Sea REEF-SPEC Carbon is the ultimate choice for marine & reef aquariums due to its unique technical characteristics. Red Sea REEF-SPEC Carbon's granule size and its micro/macro porous structure, ensures a very high total adsorption capacity and rapid extraction of the specific organic pollutants that are found in Reef aquariums. REEF-SPEC Carbon has extremely low phosphate leaching and minimal ash content while also not affecting the pH of aquarium water. Red Sea REEF-SPEC Carbon needs replacing less frequently than carbons that are not reef-specific or are of a lower quality and represents an effective, cost-efficient solution for providing the very best water quality in marine & reef aquariums.