The Ceramic Dome Water Filter (RA-CE-S) -replaces all your ZEN WATER SYSTEM FILTRATION SYSTEMS BOTH COUNTERTOP AND WATER COOLER MODELS. Filter dome made of highly compressed ceramic with diatomic properties. The surface of the dome consists of millions of pores that measure 0.2 to 0.5 micron in diameter, while most bacteria and inorganic compounds is 0.5 to 1.0 microns in size. The ceramic filter dome sits in the top holding tank. When contaminated dirty tap water passes through the pores in the ceramic filter, it will trap dirt, debris, contaminants and most bacteria before the water passes to the "clean" side of the filter. The Micro-Ceramic Filter dome made of highly compressed ceramic with diatomic properties. The ceramic filter dome sits in the top holding tank.The expected useful life of the ceramic filter is 1,000 gallons or 1 year, whichever comes first. The normal flow rate is approximately 1-1/2 to 2 hrs. for every gallon. When the ceramic is in use for the first time, the flow rate might be slow, but it should speed up in a few days. The ceramic filter dome should be handled with care. Do not use the ceramic filter if it is cracked or damaged.The recommended maintenance of the ceramic filter is at least once a month, or as often as necessary, depending on the quality of water. Over time, the trapped dirt and contaminants will begin to buildup, forming a layer of gunk on the surface of the ceramic filter. Scrubbing the surface of the ceramic dome with a scouring pad or soft brush under cool running water will unclog the pores on ceramic and expose a new layer for use.This Filter Removes up to of following contaminates:100% of Cyclospora, live Cryptosporidium & E-Coli99% of Arsenic 5, Taste, Odor & particles larger than 0.3 micron98% of Aluminum, Lead & particles larger than 0.2 micron96% of IronPORE SIZE of 0.2 to 0.5 micron (human hair is 40 to 300 microns)SILVER IMPREGNATED to kill bacteria on contactREMOVES: impurities and volatile organic chemicals such as pesticides and herbides. TRAPS: dirt, sediment, contaminants, debris, cysts and bacteriaLIFE OF FILTER is 1,000 gallons or 1 year, whichever comes firstAPPROXIMATE FLOW RATE of 1 gallon every 1.5 hours