The Micro-Ceramic filter sits inside the top tank and acts as the first line of defense. After few weeks of use, a layer of trapped dirt and gunk would accumulate on the surface, clogging the pores of the filter and slowing down the drainage of the water. (You will be glad the impurities are trapped on the filter and not consumed in your body.) The Ceramic Filter is reusable. Simply scrub it under running water with a mesh scrubber, scouring pad, or soft bristle brush to expose a new layer. It will be good as new. Remember to clean with cool water only – do not use detergent on this filter. The Ceramic Filter is designed to fit across all Zen Countertop and Dispenser models.