Super active filter medium, removes organic molecules and colour taint, enhancing water clarity in marine aquariums. Can be used to remove residues of past treatments from the water. For best results place in a high flow area of a filter for maximum water contact. Supercarb is of the highest grade for ultimate purity. Supercarb does not leach any phosphates or heavy metals. Suitable for the most sensitive reef aquarium use.Dosage Rate250g treats 800 litresRe-TreatmentChange at least every 6 weeks as prolonged use of any brand of activated carbon beyond absorptive phase can result in \"dump back\" and discharge to water