1. A method of detecting pre-conditions of scaling occurring on internal surfaces of conduits of water processing equipment, the method comprising: transmitting one or more ultrasonic signals through the wall of the conduits; deriving, in real-time, data samples indicative of spectral parameters, from received ultrasonic signals or reflections thereof; calculating a moving average of a scatter of the ultrasonic signals, over a specified period of time, based on the data samples; applying a statistical operand to the moving average, to yield a statistical distribution metric; determining a dynamic window defined by: (i) an upper boundary being the moving average plus at least a fraction of the statistical distribution metric and (ii) a lower boundary being the moving average minus the at least a fraction of the statistical distribution metric; generating a trend line being a fitting of the derived samples and monitoring the trend line within the dynamic window to detect a crossover of the trend line at the upper boundary or the lower boundary.