Dryden AFM Activated Filter Media 25KGDryden AFM The unique bio resistant activated Filter Media What is AFM? AFM Activated Filter Media is a direct replacement for sand, doubling the performance of sand filters without the need of additional investments in infrastructure. AFM resists biofouling, biocoagulation and transient wormhole channeling of unfiltered water and never needs to be recharged or replaced. AFM is a highly engineered product manufactured from a specific glass type,