The switch changes the regeneration cycle, which recharges the resin with brine. Using the wrong setting can reduce softening performance, especially if you use KCl with the controller set to NaCl. What changes depends on your model.

The Morton M45 manual says the setting “adjusts the regeneration cycle times” to account for KCl’s different dissolution rate. It doesn’t say which stages change or by how many minutes. Without your make and model, we can’t say whether the switch changes the salt dose or rinse time, or by how much. [Morton M45 manual, page 14](https://www.mortonwatersofteners.com/wp-content/uploads/2019/04/M45-7369502_C-Sm.pdf)

The controller needs to account for differences in brine preparation and regeneration performance. KCl can require more regenerant to provide the same usable softening capacity. Some machines handle this through programming; others need manual adjustments. [University of Nebraska–Lincoln Extension](https://extensionpubs.unl.edu/publication/g1491/na/pdf/view)

An incorrect setting could explain hard water, depending on which salt you use:

| Salt used | Controller setting | Possible consequence |
|---|---|---|
| KCl | NaCl | Inadequate regeneration or lower capacity than expected. Hardness may get through before the next cycle. |
| NaCl | KCl | Unnecessary regeneration adjustments may waste salt, water, or time. This is less likely to explain persistent hard water. |

These are general expectations; the effects depend on your controller.

Check the bag, match the setting to the salt, and run a manual regeneration following your manual’s instructions. Then flush the pipe and test cold water from a tap supplied by the softener.

- If the water is soft afterward but turns hard before the next regeneration, that points to insufficient capacity or incorrect regeneration settings.
- If it’s hard immediately afterward, check the bypass position, brine delivery, and the valve and resin. A blocked injector or venturi, for example, can prevent brine from reaching the resin. [Morton maintenance guidance](https://www.mortonwatersofteners.com/maintenance/common-maintenance/)

A falling salt level shows that salt is being consumed, but it doesn’t confirm that regeneration is working properly. Your make and model would let us identify exactly what the switch changes.