Eheim AKTIV (formerly EHFIAKTIV) is a activated filter carbon with high efficiency. Eheim AKTIV quickly binds pollutants, residue of medication, yellow cast and other harmful toxins in the aquarium water and traps them in large quantities, thus making the water crystal-clear. The utilisationof Eheim AKTIV is especially important after medication treatment. Use activated carbon for a limited period of time only (approx. 4 weeks) and subsequently remove or replace it. Eheim AKTIV is used in the layer structure directly downstream of the mechanical and biological filter medium and is easy to add using. To be used in fresh nad marine-water. A practical net bag is contained in the packet.