Dissolve 1 cup in 1/2 gal. cold water. Pour directly into brine well. Manually regenerate softener. Repeat for heavily fouled unit. - voilà spanking clean water softener. Depending on how rusty one's water is, repeat every 3, 6, or 12 months. According to my water department's annual report, mine isn't very rusty & I go the 12 month frequency.