Pelletized Activated Carbon By far, the best carbon in the market. Keeps fish and invertebrates healthy by absorbing numerous chemicals, organic contaminants and some metals. Removes colors and odors from aquariums and pollutants that mechanical and biological filtration leave behind. Has enormous surface area due to activation process. Three composite materials inside the pellet remove a wider range of organic contaminants. Large pellet will not restrict flow when compared to competing brands. High adsorption capacity is achieved by a wide range and quantity of internal carbon pore sizes. For phosphate free applications, pre-rinse carbon before use.