# Salt water system for pool

**URL:** <https://boards.straightdope.com/t/salt-water-system-for-pool/417812>\
**Category:** Factual Questions\
**Created:** [September 2, 2007, 4:04pm UTC](https://boards.straightdope.com/t/salt-water-system-for-pool/417812 "2007-09-02T16:04:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\
**Post date:** [September 2, 2007, 4:04pm UTC](https://boards.straightdope.com/t/salt-water-system-for-pool/417812/1 "2007-09-02T16:04:05Z")

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I have a new in-ground pool with a salt sanitation system rather than chlorine. I am slightly mystified by how it works - can somebody explain it simply, but in detail as to how this thing operates? I understand about salt dissociating into Sodium & Chlorine ions, but what are the details? There is also a setting for 20%, 40%, 60%, 80%, 100% - what does this do? I also have an indicator that tells me when to add salt. Does this work by checking resistivity, or something else?