When should I replace my salt cell?

Replace the salt cell when it stops making chlorine. Signs include low chlorine despite long pump run times and a clean cell, white calcium flakes floating in the pool, error codes like “low salt” when salt is fine, or a crusty cell. If you need to run the pump 12+ hours a day for marginal chlorine, it’s time. Salt cells last 3-5 years; replace it if it’s over four years old and acting up.