Acura, Advance, Blue Ridge, Brett Aqualine, Catalina, Coleman, D'one, Gatsby, Hercules, Hot Springs, HydroQuip, Jacuzzi , L. A. Spas, Pinnacle, Sundance, Vita, and many others

# of gallons in spa divided by 3 divided by # of bathers per day = days of use

For maximum chemical effectiveness, clearer water and longer filter life, Spa Doctors recommends not exceeding 3 months between drain and cleans regardless of the amount of use. 

To make the most of your fresh water, be sure to soak your filter in filter cleaner at the same time as your drain and clean.  Try our Leisure Time spa, filter and cover cleaners.

(And don't forget to replace your filter once a year)