A removable cartridge for use with a liquid diffusion device is provided. The removable cartridge includes a cartridge housing defining an internal housing cavity, partially filled with a liquid to be diffused, and a diffusion head positioned within the internal housing cavity with a venturi device for generating diffused liquid from the liquid contained in the internal housing cavity. The diffusion head defines at least a portion of a gas supply conduit that extends from a bottom end of the removable cartridge to the venturi device through the liquid to be diffused to enable the venturi device to be supplied with pressurized gas from an external source via the bottom end of the removable cartridge.