I am building a cheap water level sensor for hydro-test purposes, using a piezo buzzer and a 9 volt battery, wit the circuit completion done bywater shorting out the bare wires. The buzzer is loud enough on the 9 volts, but the resistance of the water does not give me onough power to hear it very well. What voltage ( DC ) should I use? or is it an amperage problem ? Any help would be appreciated.