Arctic Pure Replacement Water Filter Cartridge for AR20000 & AR40000 Filters Regular replacement of the filter cartridge in your water filtration system ensures clean, fresh water to your equipment & eliminates any offending odors or tastes. Replacing cartridges on a regular basis also reduces scale buildup in pipes or other components and helps to reduce maintenance calls. Keep a fresh replacement cartridge always on hand and make sure to replace cartridges as required will ensure that your water filtration system will continue to operate properly.