A cartridge filter is the most environmentally friendly filter option, as you do not need to backwash, which discharges chemicals into the environment and wastes water. Additionally, a cartridge filter works almost as well as a D.E. filter, so you will have remarkably clean water if you just keep your filter clean. That maintenance, however, is where this type of filter falls a little short. In order to work at peak efficiency, cartridges must be cleaned regularly, and that process is rather involved.