Use Whirlpool Water Softener Cleanser to keep your softener running as smoothly and efficiently as possible. The softener cleanser keeps your softener free of contaminants, iron and hard water build up that can affect the system and reduce efficiency. Using Whirlpool Water Softener Cleanser as recommended will extend your full-coverage warranty for an additional year, on newly purchased softeners, giving you up to 10 full years of warranty coverage! Length of warranty coverage is dependent on softener model. See extended warranty page for details.