SALT
FOR
SOFT
WATER

The only naturally "pure" water is in the stratosphere and as this comes to us through the atmosphere, as rain or snow, it picks up many impurities, such as dust and gases. These substances make the water slightly acid so that, as it travels over and through the ground, it dissolves a certain amount of the mineral matter of the soil or rock with which it comes in contact.

This dissolved mineral matter makes water "hard" and unsuitable for many home and industrial uses. Fortunately, the principal offenders are calcium and magnesium compounds which are relatively easy to remove.

There are various methods for removal of these "hard" compounds, the most familiar one is by passing the water through a "water softener" which is a machine filled with a sodium compound. The process works by trading the sodium in the compound for the calcium and magnesium in the water. This procedure is called "ion exchange" and it makes water "soft".

After there is no more sodium to trade, it must be replenished and this is done by another trade for the sodium in common salt which is passed through the softener as brine. The calcium and magnesium, gained by the brine in the trade, are washed away and the softener is again ready for further trading.