Recently my 5 year old SWCG stopped working properly. It had more than 10,000 hours on the cell. I decided not to replace it ($900.00 cell only cost) and to go back to my liquid chlorine feed system (Stenner pump controlled by iAqualink). I have decided to let the salt concentration (4000 ppm) to dilute naturally over time. My question now becomes: Should I use my Total Dissolved Solids (TDS) measurement, instead of salinity, when using Pool Math to calculate the CSI? My reasoning is that I no longer need to track my salinity levels. By the way, I measure my Salinity, pH and TDS with an Apera PC 60 which I calibrate monthly.