Crystal Carb is a selected activated carbon specifically for freshwater aquariums. Its incredible active surface of 1300 m2/g makes it capable of adsorbing up to 24g of methylene blue per 100g of carbon. It complies with the UNI ISO EN 12915 Granular Activated Carbon for use in the treatment of water intended for human consumption. It is particularly useful for a continuous removal of organic pollutants colorants (phenols) pesticides medicines chlorine derivatives and compounds that cause bad odors. Wash in pure fresh water before use. Dosage: 50 ml of product per 100 liters inside the filter to be replaced every 30 days depending on the condition of the tank.