Abstract: An audio-visual alarm apparatus is provided for use with a water quality monitor having a pair of monitor nodes across which electrical conditions are indicative of whether the measured water quality is inside or outside of an acceptable quality range. The apparatus includes an audio-visual alarm and a circuit for energizing the alarm when the electrical condition across the monitor nodes is indicative of a measured water quality falling outside the acceptable range. The circuit includes a first relay for maintaining the circuit in a normally open position, and for closing the circuit when the relay is connected to the monitor nodes and a voltage condition across the monitor nodes is indicative of a measured water quality outside the acceptable range. Further, for certain monitors, it is possible to bypass the first relay by connecting the circuit directly to the monitor nodes.