3rd unit in less than 4 yrs, version 2.0. Warranty won't cover it. PPM salt per Taylor drops is repeatedly 3400-3800. Unit says it's 2200. Last week I re- installed unit with 71 degree water and it read 3200 and made cl. Close enough. Cold front this past week cooled water. Pentair says it needs 70 plus to work. Huh? My previous units didn't need such warm water to make cl. This unit is 15 months old. Started giving false low readings last Nov. Acid washed twice, no change. Day to day ppm readings varied over 2000 with one or 2 degree water temp changes. Removed unit for the coldest months and stored indoors. My previous unit acted the same way. That one was replaced under warranty and worked from day one until last Nov. I know the salt reading is temp. compensated. Perhaps it's a bad temp probe? Recommendations?