IMPELLER:  The rotating vanes of a centrifugal pump; its action creates the flow of water. The impeller is shaft driven by an electric motor.

INFLUENT:  The water coming into and up to the impeller from the suction lines. These pipes are under vacuum pressure.

ION: An atom, or group of atoms that possess an electrical charge.

IONIZER:  An ionizer is a device mounted on your return line, and through which water flowing will receive charged metal ions. Manufacturers may use a copper anode and/or silver. Copper is an algaecide and algaestat, while silver is known for its properties as a bactericide. This electric, limited technology has been replaced by the Vision System.

IRON:  Usually introduced into the water from iron plumbing or from well water, Ferric Iron can stain surfaces, while Ferrous Iron will turn your water a clear green color.   

JANDY VALVE:  A brand name of a three way valve, which has simplified pool plumbing.

JET PUMP:  Used in spas to provide additional thrust into the hydrotherapy jets.