DE filters are great. They filter down to something like 3 microns. You need not buy cartridges for them. If you keep your pool clean they're pretty low maintenance, requiring backflushing and reloading of the DE or Fiberclear powder every month or so. But at least once a year, and probably more often unless you keep your pool absolutely immaculate, you need your entire filter assembly, including the grids, cleaned. I've had to have mine cleaned twice in about 6 months.