This is the first home we have had with a water softener. Unit is a six years old North Star softener. I add salt about every four month. I know how the thing works from being in power generation where we had large softeners for making boiler condensate. I check the North Star venturi once a year and have never found one speck of anything in it. Use broom handle to check for salt bridging periodically. North Star unit stopped making soft water. Checked for error codes and found none. Checked fill valve and it was clean and operable. Unit cycled through various stages correctly. Had unit regenerate three nights. No soft water. Problem was(I spent all morning removing salt pellets and salt mush from tank)there wasn't any brine being produced Just mush.As I understand softener operation, after the initial three gallon start-up fill, the softener first adds fill water, pulls brine into resin tank, ion exchange, rinse and back flush. Any suggestions about how to keep this from reoccurring will be appreciated.Thanks