A fluid jet for injecting fluids in the liquid of a tub through a throughbore in a wall of the tub comprises a gas injector with a hollow body having a gas inlet receiving a gas flow from a pressurized gas source. A gas outlet produces a flux of gas with the gas flow. A liquid injector comprises a hollow body with a liquid inlet connected to a pressurized liquid source to receive a liquid flow therefrom. A liquid outlet produces a flux of liquid with the liquid flow, the gas injector being received in the hollow body of the liquid injector, for the gas outlet and the liquid outlet to form a common jet outlet. The liquid injector is secured to the wall of the tub opposite the throughbore such that fluids exiting the common jet outlet are directed concurrently through the throughbore into the liquid of the tub.