A layer height measuring system in one embodiment has a transmission line including a probe for measuring a height of a first layer within a tank and a cable that connects the probe to an electronics unit. The electronics unit cyclically transmits interrogation pulses to the probe and receives reflections therefrom for time domain reflectometric measurement of the height of the first layer. The layer height measuring system may also have a memory and a processor configured by the memory to perform the steps of detecting first and second impedance transitions corresponding to first and second boundaries of a bounded region of known length; optimizing a sweep offset and a sweep gain so as to cause swept sample collection to occur substantially only within the bounded region; and detecting a third impedance transition within the bounded region, the third impedance transition corresponding to an interface between the first layer and a second layer, the first and second layers having respectively different dielectric constants.