Hard water and filter life for HAF-QIN/EXP
Know that refrigerator carbon filters are not water softeners. The published Samsung record identifies this cartridge as HAF-QIN Refrigerator Water Filter.
Start with fit verification
Match the complete refrigerator model and the code printed on the existing cartridge. Samsung's product page lists compatible model families including BRF365200, BRF425200, RF18A5101, RF20A5101 and RF22R7351. Do not infer compatibility from color, overall shape or brand alone.
Service baseline
The available record uses 6 months or 300 gallons, subject to the manufacturer’s whichever-comes-first instructions. Water quality, usage and long periods of inactivity may justify earlier service.
Safe action
Turn off the water supply, unlock the old filter counterclockwise, insert the new filter and turn clockwise until locked. If the cartridge does not seat normally, water does not return after flushing, or the housing leaks, stop and use the refrigerator’s model-specific manual.
Evidence
Open the linked source before purchase. FilterRef separates published compatibility from general troubleshooting guidance and does not treat an aftermarket cross-reference as automatically equivalent.