The Doulton W9121750 Super Sterasyl ceramic candle cartridge features an absolute filtration rating of 0.9 microns and a nominal rating of 0.5 microns. This tight pore structure allows the ceramic shell to mechanically block pathogenic bacteria, cysts, sediment, rust, and particulate matter while allowing beneficial minerals to pass through. The self-sterilizing silver-impregnated ceramic also inhibits bacterial growth within the filter itself, making it one of the most effective gravity and undersink ceramic filtration solutions available.

The Doulton W9121750 has a rated filtration life of approximately 6 months or up to 600 gallons, whichever comes first, under typical municipal water conditions. Unlike disposable carbon cartridges, the ceramic shell can be cleaned multiple times during its service life by gently scrubbing the exterior under running water with a soft brush or Scotch-Brite pad to restore flow rate. Replace the candle once the outer ceramic layer has been reduced through repeated cleanings or after the 6-month mark.

The W9121750 Super Sterasyl candle is specifically engineered to reduce pathogenic bacteria (E. coli, Salmonella, Klebsiella, Shigella) at >99.99%, cysts such as Cryptosporidium and Giardia at >99.99%, turbidity, sediment, and fine particulate matter. The silver-impregnated ceramic provides bacteriostatic protection to prevent mitosis (bacterial grow-through) inside the cartridge. Note that this specific candle focuses on microbiological and particulate reduction — it does not contain an activated carbon core, so it is not designed for chlorine or chemical taste and odor reduction.

Yes, the Doulton W9121750 Super Sterasyl ceramic candle is tested and certified to NSF/ANSI Standard 42 for aesthetic effects and has been independently tested against NSF/ANSI Standard 53 protocols for cyst reduction. Doulton ceramics are manufactured in the UK to ISO 9001 quality standards, and the Super Sterasyl technology has been trusted for over 180 years in residential, humanitarian, and emergency drinking water applications.

The Doulton W9121750 is a 7-inch short-mount ceramic candle with a standard 1/4-inch BSP threaded mount, making it a direct replacement for Doulton HIP, HIS, and HIP-Rio undersink systems, as well as other undersink housings designed to accept short-mount Doulton candles. It fits the Doulton Ultracarb housings when used as the pre-filter stage (without carbon) and is interchangeable with the Doulton Sterasyl and Super Sterasyl short-mount candle line. Always confirm your housing accepts a 7" short-mount threaded candle before installation.