Methods for monitoring scale deposition in a water-containing industrial process are disclosed. In certain embodiments, the water-containing industrial process is an aqueous cooling system. In certain embodiments, the methods incorporate fluorometric monitoring and control techniques along with a piezoelectric microbalance sensor. A particular embodiment of a piezoelectric microbalance sensor is additionally disclosed, along with at least one method for using the particular embodiment that is independent of whether fluorometric monitoring and control techniques are utilized.