Abstract: A carbonate spring bath system creates a bath water dissolved with CO.sub.2 gas and supplies the same to a bathtub. The system includes a source of a concentrated CO.sub.2 gas, a circulation path connected to the bathtub and including a booster pump for circulating a bath water from and into the bathtub. CO.sub.2 gas and air supply lines are connected to the circulation path upstream of the pump. The CO.sub.2 gas and air supply lines includes valves which are opened and closed to provide the CO.sub.2 gas and the air at a suitable mixture ratio such that the CO.sub.2 gas and air are forced to dissolve in the pressurized bath water. Disposed downstream of the pump is an accumulator for separating undissolved gas in the bath water and storing in a gas chamber the undissolved gas emanating from the bath water. A recycle line connects the gas chamber to the circulation path upstream of the pump to return the undissolved gas to the circulation path.