Richard, again you are correct. I thought about wording my statement differently, and I guess I should have now. TDS has does not really say you have salt in the water, but TDS will go up as the salt levels do. TDS is measuring all dissolved solids in the water. The reason you have a higher tds when using liquid chlorine is because liquid chlorine is sodium hypochloride, which contains salt. So all I am saying is that TDS levels will be the highest in pools that use liquid chlorine, with the sodium causing that. used to be that when tds got 1000-1500, pool stores would tell you to do a partial drain to dillute it, as you might have a hard time dissolving any solids in it. Well now with salt water systems, tds is up to 4600 or more, with salt levels being at 3200.