The innovative easycrystal filter pack c 250300 is suitable for use with the easycrystal filter 250 and the easycrystal filterbox 300 the filter cartridge ensures healthy crystal clear water due to its intense mechanical chemical and biological filtration quick and clean replacement for optimal filtration change out the filter cartridge every 4 weeks no need to wash out the filter media and no more wet hands important the green side of the filter cartridge must face the front of the f