EHEIM KARBON is particularly suitable for water purification during the set-up phase of the aquarium. In particular, chlorine from mains water and other chemical substances, which can get into the aquarium during installation, are safely taken up. EHEIM KARBON should be used for a short time (ca. 4 weeks) in the layering set-up after the mechanical (e.g. EHEIM MECH or MECHpro) and the biological filter media (e.g. EHEIM SUBSTRATpro) in the net bag provided. - Binds chlorine and other chemical substances - Use e.g. during set-up or after treatment with medications - Use for a short period (ca. 4 weeks) - Only suitable for fresh water Tip: Only use adsorptive filter media for a few weeks, as the harmful substances are only attached and can loosen after some time and be reintroduced into the water. At the very least they should be changed regularly. Normally adsorptive filtration is only necessary during aquarium set-up or after treatments with medications.