British Berkefeld filters use the age-old process of micro-porous filtration used by nature coupled with modern state-of-the-art technology and the highest quality materials to produce one of the finest water filtration systems available anywhere. At the core of the sub-micron ceramic filter is the most basic of elements: Diatomaceous Earth. This is the same substance, which artisans refine into exquisite porcelain and pottery. The microscopic pores of the ceramic filter element make it an extremely efficient filter for the reduction of particulate matter, pathogenic bacteria and fine sediment from water. Minute particulate matter will quickly plug media style filters, but the ceramics have the added benefit of being re-cleanable and re-useable. The Super Sterasyl element, used in Berkey systems, utilizes the latest technological advances of ceramic filtration by incorporating pure silver impregnation into the porous ceramic shell to inhibit the growth of bacteria. Furthermore, the Super Sterasyl ceramic filter elements contain activated carbon, which reduces unwanted chemical and organic compounds from the water while also improving taste. Each filter can be cleaned many, many times before needing replacement. If using tap water, the filters will normally only need to be cleaned every 6 months. You will know when your filters need to be cleaned because the filtration rate will slow down. To clean, simply rub the filters with a scotch-brite pad under running water (as in the picture above). The carbon inside can also be refreshed by boiling the filters for 5 minutes.