The Flowclear Chlorinator is designed to be installed in a swimming pool’s return line. The device produces up to 12 grams of pure chlorine per hour and introduces it into the water as a part of the pool’s daily filtration cycle. The Flowclear AquaFeed Chlorinator, also designed for installation in a swimming pool’s return line, serves a function similar to that of the Flowclear Chlorinator. The AquaFeed Chlorinator introduces chlorine into a swimming pool; however, while the Flowclear Chlorinator produces its own chlorine, the AquaFeed Chlorinator relies on dissolvable chlorine tablets.
[1] Please importantly note that only the relevant portion of the related is displayed above. You may refer to the said customs ruling for the entire ruling explanation.
[1]. https://rulings.cbp.gov/ruling/N299754