I have a Crystal Pure Salt system PL7700 that I purchased in June 2016. I am having issues with it this year. It keeps telling me that my salt is low but when I take the water to be tested salt reading are at 4100 PPM. I have cleaned the salt cell twice. Is there a way to recalibrate the salt reading or do I need to purchase a new cell. I would be disappointed if I needed a new cell since the replacement is a much as I paid for the complete system originally.