CerMedia MarinePure MP2C Bio-Filter Media for Koi and Goldfish Ponds, 2 Cubic Feet
Ceramic Bio-Filter Media with Vast Surface Area and Open-Flow Porosity. Designed for ammonia & nitrite removal; 2" cubes designed for the high flow of Koi & Goldfish ponds and recirculating aquaculture systems; Use extra-large filters and shower filters.