This side conversation was removed from here. JasonLion
My SWG requires 4500 ppm (yes, you read that correctly). Using pool calculator I add the required amount of salt. I never test. As long as the SWG reads green, I assume it likes the salt level. On the rare occasion that I reads low (usually halfway or further into the swim season - splashout) I raise it by 500 ppm (using pool calculator to determine the amount). No issues. I have a cheap $150 SWG just starting its 4th season.