The three main categories of pool filters are: DE Filters, Cartridge Filters, and Sand Filters which, respectively, can filter particles as small as 5, 10, and 20 microns.
Cartridge Filters are removed from the filter and cleaned with running water and a cleaning solution, if necessary. DE and Sand Filters are subjected to “backwashing” pool water to clean debris from the filter media.
This process can commonly take 2-300 gallons of water that will then need replaced, resalinated, and rebalanced. Cartridge Filters are the most water-efficient and are easiest to maintain, while DE filters give you the most effective filtration.