Whirlpool tubs initially became well-liked from the U.S. over the sixties and 1970s. A spa is also called a "jacuzzi" there, because the word turned a generic soon after-plumbing component manufacturer; Jacuzzi introduced the "spa whirlpool" in 1968. Air bubbles could be launched into the nozzles via an air-bleed venturi https://pool.net/stahlwandbecken-pool/