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Water - Solubility - Ions

Methods used to Soften Water.

Apart from boiling, hardness can be removed
from water by using washing soda
or an ion exchange column in a water softener.

What is Washing Soda?

Washing soda is sodium carbonate.
Adding sodium carbonate to hard water
will precipitate insoluble calcium carbonate
or insoluble magnesium carbonate.
This is a way of removing permanent hardness from water.

What is an Ion exchange column?

A water softener uses an ion exchange column.
An ion exchange column is a glass tube filled with a resin
containing sodium ions.
Calcium (or magnesium) ions in the water become exchanged
for sodium ions as the water flows through the column.

Eventually, the column becomes saturated in calcium ions
and stops being effective. The column can be regenerated
by pouring sodium chloride solution (salt water) through it.
The calcium ions are flushed out and replaced with sodium ions,
allowing the column to be reused.

For more information about how a water softener works
please click here. A water softener is different from a scale inhibitor.

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