Home Products Replacement Filter Cartridges & Housings The Water Doctor is an authorized sales and service dealership for Excalibur Water Systems. Replacement Filter Cartridges & Housings The Water Doctor has a variety of replacement filter cartridges as well as standard and jumbo filter housings. Filter Cartridges & Housings Acid Washed Coconut Shell Carbon Block CartridgesView Details Doulton Ceramic Sterasyl CartridgesView Details Doulton RIO 2000 Filtration ModuleView Details Doulton Ultra Carb Ceramic CartridgesView Details Dual Gradient Density Polypropylene CartridgesView Details Enalka Neutralizing CartridgesView Details Granular Activated Coconut Shell Acid Washed Carbon CartridgesView Details Jumbo Filter HousingsView Details Jumbo Filtration SystemView Details 1 2 →