Salt Level Issues

Two days ago I took a water sample to my local pool supply store and had the sample tested. I was told that the total and free chlorine level was at 0.5, PH 7.2, Alkalinity 70, Calcium hardness 85, Stabilizer 22, and Salt 4100. I was then told to extract around 1- 1.5 inches of the water level and add fresh water. I did as told. The water is now green again and the Hayward salt system is reading a salt level of 0. It also has the check salt and inspect cell lights on. I disconnected the cell, checked for deposits which there were not any, and rinsed out the cell. Connected everything back up and is still reading a salt level of 0. How does the salt level change that much in 2 days? If the salt level was that high to begin with why would the chlorine level be so low? Could the salt cell be dysfunctional?

Pool: Should be around 35,000-40,000 gallons, vinyl liner, brand new sand filter

Matthew - The salt cell will provide an inaccurate salt reading when it goes bad. The cells have an average lifespan of three years.

Check out the AquaRite troubleshooting guide. It has a lot of good information on what to look for when there is an issue.