Filter cartridge cleaner. 1 tablet cleans up to 2 cartridges. Fast acting fizz tablet, no measuring. No messy chemicals. Releases body oils, sun tan lotion and dirt. Safe and easy on the filtration fabric. Loosens debris from the fabric surface. environmentally friendly. easy to use. Rinse cartridge. add 1 tablet to bucket of water. soak cartridge for 25 minutes. Rinse cartridge and replace back into hot tub.