does it need replacing also what do you guys use in you emiem 2250? thanks http://www.aquariumguys.com/ehfilav.html
Eheim Ehfilav 5 Liter
EhfiLav is an ideal biological filter media where excessive mechanical debris is present. The rough surface of the volcanic material offers the ideal adhesive surface for bacteria colonization. Suitable for freshwater, and pond set ups, use a filter bag for easy maintenance.