While cartridge filters are more popular in use with spas and hot tubs, there are still quite a bit of variety suited for pools. The cartridge filters are cylindrical in shape, and are composed of dozens of pleats, which serve to filter and clean your water as it passes through your equipment system. Capable of filtering down to a range of 25 to 100 microns, the filter cartridges are still a viable option for filtering your pool. The cleaning and maintenance is not as care-free as the sand filter, as they do not feature a backwash setting and must be removed from their tank for a thorough cleaning.