Multi Filter Spare Fontana Aqua is a multistage filter for Aqua fountain. The filter is equipped with a 4-stage cartridge capable of eliminating chlorine, heavy metals and bad odours. The filter consists of: sponge (captures coarse impurities; Manganite (removes heavy metals; Ion exchange resin (removes pollutants present in mains water such as heavy metals); Coal vegetable (removes bad odours and impurities). The replacement of the filter is suggested by the fountain itself through a special sensor, every 8 weeks of use. Simple to replace allows your dog or cat to always have clean water.