It is used with a multilayer filter minerals.The largest suspended substances are kept in the top layer of the filter, which is composed of coarse and light material. The smallest particles are kept in the lower layers, which are composed of the thinnest and highest specific gravity minerals. Due to the fact that the minerals have different sizes, the minerals automatically settle down by taking their former positions after the backwashing process. Multi media filters are designed with special diases according to needs.