With low mineral content add 1 ounce per/100 gallons on initial fill and .5 ounce per/100 gallons weekly. Example: on a 300 gallon spa add 3 ounces on initial fill and 3 ounces weekly.

With high mineral content add 3 ounces per/100 gallons on initial fill and 1.5 ounces per/100 gallons weekly