The sponge filter provides both mechanical and biological filtration - it captures floating sediment without sucking your baby in and provides an ideal place for bacteria to colonize. It is perfectly adapted to salt water and fresh water. Suitable for aquariums from 75 to 200 litres]. Super quiet air sponge filter, featuring a high density 60 ppi porous fine sponge, provides an ideal place for the colonization of beneficial nitrifying bacteria , making the aquarium water clearer and closer to natural water quality. Easy to install: connect one end to your air pump with an air hose and the other end with this propeller tube installed which is equipped with a check valve on the air hose to prevent water backflow and damage to the air pump in the event of a power failure. Solution aeration and filtration - a great way to cleanse and oxygenate. Easy to use and clean: when you place the sponge in water, air is squeezed into the sponge . It is then absorbed by the water and remains there.