We had a leak at the end of the summer so I just had to add 440# of salt. My Hayward PL-P-4 is reading 4700 ppm salt on our T-CELL-15. My salt test is reading 2800, which is lower than I expected it would be, but I did the test while the salt was still dissolving. However, this afternoon I checked it again on the PL-P-4 and it is still reading 4700. What can I do to get it to read correctly? It has never been as accurate as my salt test, but it has never been this off.