You can eliminate the alarm by bypassing the sensor. The circuit will not work any more but the alarm will go out. You connect a 2000 ohm resistor between the probe wire and the plus of the battery by using the ignition line or the accessory line. If you connect directly to the battery the probe wire will always be drawing electricity and can drain the battery after a few weeks of not starting. Do not connect the probe wire directly to the battery, the CMS will be damaged.
The probe itself when properly installed senses a specific voltage from the battery, around 5 volts. If the water is low the probe does not sense voltage and triggers the alarm. Also if the battery is weak the voltage at the probe will be low and that will trigger the alarm as well. Test your battery and charging system to make sure there is not a problem there.