I have a Jandy Aquapure about 7 years old. I am getting a %chlorine and then flashing "LO". The sensor is just flashing Green with a No Flow reading. I have cleaned the cell, taken off the sensor to make sure nothing covering, cleaned all baskets and so on. Still "no flow" and flashing green. Had a very unusual salinity reading of 4100 and have been flushing and adding water, down to 3700. Is there a way to tell if the sensor is bad?