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What actually happens when you soften water by ion exchange?

Harvey water softeners typically treat the water to the whole house. They are salt-regenerated, ion-exchange units which contain ion exchange resin. This resin contains sodium ions which “swap places” with calcium (together with magnesium and some other trace metal ions such as iron and aluminium) as the water passes through. So calcium and magnesium are taken out of the water and sodium is put in. 

When the sodium ions on the resin are used up, the softener performs a regeneration cycle. The regenerant is common salt (sodium chloride) solution (brine) and, during regeneration, the exchange process is reversed so sodium goes back onto the resin and the calcium and magnesium are flushed out into the drain. The resin is then ready for its next softening cycle. 

Because Harvey water softeners use a twin cylinder design, there is no interruption to your softened water supply during the regeneration process. The cylinders do not regenerate at the same time. While the resin in one cylinder is regenerating, the other continues softening your water. You can read more about this in our How a Water Softener Works guide 

Find out more about the resin inside your Harvey water softener on our resin information page 

Harvey is the UK’s number one brand for water softeners. Your Harvey water softener simply connects to your home water supply, slots under the sink, and begins the softening process. You can book a no-obligation demonstration with one of our experts to learn more about our water softeners – get in touch today. Book now