A liquid dispensing system is provided for automated dispensing of a plurality of liquid reagents into a recreational body of water. The liquid dispensing system includes a cartridge apparatus housing a plurality of liquid reagent containers, each containing a respective liquid reagent. A docking assembly is provided having a dock manifold device, and is releasably coupled to the cartridge apparatus between a first condition and a second condition. In a first condition, the cartridge apparatus can be removably coupled to the docking assembly, while in the second condition, the cartridge apparatus is lockably mounted to the docking assembly in a manner permitting fluid communication from the respective reagent container to respective fluid passages of the manifold device. The dispensing system further includes a dosing engine having a valve manifold device to selectively dispense the liquid reagents into the recreational body of water through a dispensing port.