The Doulton filter is unique because it is actually three filters in one. The silver-impregnated ceramic traps and reduces parasites while removing rust and dirt. The extruded carbon block reduces chlorine. A heavy metal removing compound is mixed in with the carbon block to remove lead. Other filters, which are usually made with block carbon, can trap parasites, but not as efficiently because their pore sizes are not as consistently small as the Doulton.
Bacteria can actually breed in block carbon filters.
The life of the Doulton filter can be extended by proper care. The ceramic filter can easily be removed and scrubbed with an abrasive pad under cold water. The filter is effective for one year or 600 gallons of filtration. After one year, chlorine, chemicals, and lead are not removed as efficiently. Replacement filters are available for all models.