My intention is to use two adjustable weirs to distribute (will not necessary be equal) sewage plant influent to two clarifiers. Weir controlling will be done remotely by monitoring head over the weirs through 4-20 ma signals. The head over the weirs can vary depending on the influent, and, the flow desired to be sent to each clarifier. Under these conditions, unlike in a fixed wier scenario, the head over the weirs can vary. Is it still possible to use a US sensor? If so what is the best way to calibrate the sensor?