At the core of the British Berkefeld Doulton® ceramic filter element is the most basic of elements...EARTH. This is the same substance which artisans, first in Asia then in Europe, refined into exquisite porcelain and pottery of the Shoguns and Kings. This material is Diatomaceous Earth [D.E.], a fossil substance, made up of tiny silicon shells left by trillions of microscopic, one celled algae called diatoms that have inhabited the waters of the earth for the last 150 million years.

Diatoms have one property that sets them apart from other micro organisms. They weave microscopic shells which they use for the protection and locomotion. These shells are covered with a pattern of tiny holes so regular that even the slightest change in their design usually signifies a different species. As the diatoms died, their shells survived, slowly piling up in deposits at the bottom of geological lakes and lagoons. When these lakes dried up, what remained were huge deposits of "diatomaceous earth". Today there are over 1500 uses for Diatomaceous Earth, from abrasives for toothpaste, filtering agents for water and milk, heat insulators for kilns, to polishing agents in nail polishes, and many many more.

The latest designs of Doulton® filter elements incorporate pure silver impregnated into a porous ceramic outer shell [80,000,000 pores] that can trap bacteria down to as low as .22 of a micron in particle size [1/100,000 of an inch]. Laboratories consider a filtering medium with an effective pore size of .01 micron to .45 micron to be bacteriologically sterile and .45 micron to 1.0 micron to be bacteriologically safe. Regrowth of bacteria that becomes trapped either on the outside of the element or in the ceramic's pores is controlled by the silver which, on contact with water, releases small quantities of positively charged metals ions. These ions are taken into the enzyme system of the bacteria's cell and thereby neutralize it. The flow rate of the ceramic filter can be easily renewed by simply brushing its outer surface under running water. As the top layer of ceramic and the contaminants are brushed off and flushed away, a new layer becomes available. This process can be repeated dozens of times before the ceramic material is exhausted.