I replaced the flow switch on my pentair swg 40 and it still reads low salt. Salt tests fine at 3600. It’s 8 years old. Hours test show at 20%. No scale on fins. If it’s only around 2,000 hours of operation I can’t seem to think I need a new one (unless that’s off as my rough estimate would put the unit at 5,000-6,000 hours). Do I need to fork over the 1200 for a new one?