Soft water is soft because the calcium and magnesium minerals have been removed.

Q. How does water become hard?

A. In nature, water moves through a cycle, from soft to hard to soft.

Rainwater is naturally soft. After falling to earth, it may pass through or over rocks and other ground formations, dissolving minerals and carrying them off. if it later flows into a lake and evaporates, the water is softened naturally: the vapour rises, leaving the minerals behind. Water drawn from rivers, wells, or other ground sources may have dissolved enough minerals to be considered hard.

Q. How can water be softened?

A. There are two common softening methods. One method is the use of a sequestering agent. A chemical added to the hard water attaches itself to the hardness minerals, isolating and neutralizing them. Detergents contain some amount of sequestering agents.

Second, water can be softened by ion exchange. This is the most common method used in home and commercial softening. Hard water flows over beads of ion-exchange resin in a tank. The resin has been coated with sodium ions, taken from salt brine when the softener regenerates. The beads attract and hold the hardness minerals and replace them with the sodium ions. Removal of the calcium and magnesium minerals makes the water soft.

Q. How can you tell if water Is soft?

A. Mix several flakes of pure soap (such as Ivory Snow) with 3/4 of a glass of water Shake it vigorously. If the water and soap form suds that last several minutes, the water is soft. If no suds form, or if a scum or film becomes visible, the water is hard.

This simple test is , in fact, -the most common scientific method of The flask on the left contains water "treated" by a catalytic conditioner. The flask on the right contains water softened by ion exchange. Note the difference in suds.distinguishing hard water. Soap always forms a curd when mixed with calcium and magnesium, and always forms suds or a lather when the hardness minerals are absent.

Be sure to use pure soap for your test, not detergent. Detergents contain sequestering agents to overcome hardness chemically, thus making the! test invalid. The curd or scum created by the minerals in hard water is what causes bath tub ring, makes clothes stiff and grey, puts spots on glasses and cutlery, and forms scale in hot water heaters.