should use 2.5 teaspoons after light use, 1-3 people for 10-20-mins. Over 20mins or up to 6 people add 5 teaspoons once done, and run the clean cycle when adding. 5 teaspoond to shock once a week.
Having ozone and freshwater cartridge, you can go to the everfreshwater care system, you already have 2 of the four components. if you have mps you have 3 of the four components. the last component is the pre-filter.
With everfreshwater care, chlorine is used weekly to shock and once a month to shock and wipe topsides of spa and underside of cover.
your regular addition is mps prior to each use and nothing when you get out. I beleive the dose is 1 teaspoon per 100 gallond of mps prior to each use and you can enter the spa without waiting.
I'll double check when i get to the store tomorrow. If you have a fax machine i can fax you our maintenance sheet for everfreshwater care for the grandee tomorrow.
there are test strips for mps.