Times based 2510 series water softeners are used when you want to regenerate your softener based on time. Usually softeners are designed to regenerate at least one a week to keep the resin clean and bacteria free. For people who do not use enough water to regenerate at least once ever 2 weeks, It is recommended that you use a water softener that is timer based instead of one that is meter based. Softeners in this group regenerate based on time.