Your salt level is increasing because you are adding hydrochloric acid (HCl) to control the pH so that is where the chloride is coming from. The acid lowers both pH and TA so when you add sodium bicarbonate (NaHCO3) to increase the TA, you are adding sodium. So between the acid and the baking soda, you are increasing sodium chloride -- salt. The following table shows you what is happening:

......................................... pH ...... TA ....... Na+ .... Cl-
Carbon Dioxide Outgassing ..... + ......... 0 ......... 0 ........ 0
Adding Acid ......................... - .......... - ......... 0 ........ +
Adding Baking Soda .............. 0 ......... + ......... + ....... 0
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Net Result ........................... 0 ......... 0 ......... + ....... +

Na+ is sodium, Cl- is chloride, and sodium chloride is ordinary table salt and is what is used in the pool at an elevated level for the SWCG.