Hot Tub SERUM Total Cleanse is a highly concentrated jell designed to deep clean (or purge) your spa by removing biofilms and accumulated deposits hidden away in your spa’s plumbing. While most other purges require 24 hours, Total Cleanse requires only 20 – 30 minutes to completely clean your spa. It will also clean your filters while cleaning your spa. A single 2 oz. jar of Total Cleanse will clean a 400-gallon spa twice. It is recommended to purge a spa at least once a year, hence our 2 oz. jar will keep a typical spa clean for 2 years.