11 water filtration and purification units and replacement cartridges and filters therefor; apparatus and filters for water purification and water filtration for pools, spas, fountains, water features, water slides, water rides, and water parks; water treatment apparatus for pools, spas, fountains, water features, water slides, water rides, and water parks, namely, water filtration systems, chemistry control and monitoring systems, chemical treatment systems, supplemental oxidation systems, and water pump circulation systems