This 100sq.ft. filter cartridge is used in the Caldera Utopia series hot tubs. If you have a Tahitian, Niagara, Geneva, Cantabria, or Florence Caldera Utopia series hot tub, this is your correct filter cartridge.
This cartridge measures 16 1/2″ long by 8″ in diameter. It has a 3 1/2″ bottom opening and a closed handle top.
You should change your Caldera hot tub filter cartridge once a year and rinse it once a month.