I have a Hayward Pro Logic salt system that is running the GLX-PCB-PRO main board. About 2 months ago, I started to get low, then very low salt readings (2000 ppm then down to 1900 ppm). Naturally I added salt only to see the ppm go up slightly to 2100 ppm. I added one more 40 bag and when there was no change, I took a sample in to have it tested. To my total amazement, the salt level wad 4800 ppm. I figured that the salt cell was failing so I purchased a new T-15 cell. Installed it and verified that the system was still configured for the T-15. I got a ppm reading of 5200 ppm with this new cell. After 5 days, the salt reading would very between 5000 and 5200 ppm. Since my original salt level was 4800, based on the water analysis I had done, I drained the pool down and added fresh water. No change in the salt reading as it would never go below 5000. I went through the calibration exercise listed in the manual several times and I checked and double checked the Volts and Amps (24.02 v and 10.08 a). According to the manual, both those numbers are within range. I then made the assumption that maybe the new salt cell was malfunctioning. I returned it for a new replacement and to make a long and frustration story shorter, there is not change other than I have seen the salt level drop to 4800 but then overnight it shot right back up to 5200. I tested the water manually just to make sure and the reading was 3800. Any suggestions as to what is going on and what can I do to fix this issue? Thanks