as stated earlier, marquis use an inline delivery system with bromine combined with a cartridge of minerals. from my own experience in the show room, bromine has worked fine. the only draw back to the floater/inline system is that in a larger tub like yours, the bromine cartridge only last about 3 weeks depending on use/filter cycles/etc. but dont fret, there are bromine tablets available also.
other than a sanatizer and shock, you will want to get filter cleaner (and a 2nd set of filters if it wasnt included from the preveious owners)....other items are available (spa perfect/clarifier/others) can be grabbed as needed.