A system for determining a fluid level in a pressurizable container comprising is disclosed. The system includes a service valve having a set of wrench flats defining parallel flat surfaces, one of the wrench flats having a recess defined entirely within its flat surface, a stop-fill device interconnected with the service valve and operable to rotate a first magnet inside the service valve in proximity to the recess in proportion to the amount of fluid in the pressurizable container, and a dial assembly having a dial face and a pointer attached to a second magnet, the second magnet housed in a magnet protrusion on a side of the dial face opposite the pointer and operable to fit into the recess in the service valve such that the dial moves on the dial face proportionately to the degree of rotation of the first magnet inside the service valve. In one variation, a sensor placed in the recess or adjacent a throat of the service valve is electrically connected to a remotely located gauge for displaying a reading corresponding to the level of fluid in the container.