After the initial dosage of salt, you will only need to add salt when necessary. The most common ways salt is lost is through leaks, rainwater overflow, filter backwashing, and bather splashout/carryout. Normal water evaporation does not lose salt, it increases the concentration. The make up water added to bring the water level back to normal will then reduce the salt concentration back to 3000 ppm.
The Digital and Soft Touch units both have low salt indicators, with the Digital going further to provide the proper salt amount needed to reestablish 3000 ppm (based upon the programmed pool volume input).
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