Kiesel filter

A germ filter is a filter used to purify water in ponds and swimming pools. Kiesel filters, sponge filters or filter cloths have such coarse openings that the fine turbidifying dust particles pass through them. These so-called coarse filters can only become effective in combination with flocculants (such as aluminium sulphate). These flocculants are shaken into the water and cause the fine turbidifying particles to coalesce into larger clumps so that they can be collected. To filter the finest particles, one should use a diatomaceous earth filter.