FAQ

Water is a tasteless, odorless, colorless liquid in its pure state. Pure water seldom exists, but contains gases and solids picked up from various sources.

Water can become contaminated with foreign substances, either by picking up natural impurities in the air and earth or by dumping of sewage or trade wastes into streams, etc.

Natural impurities picked up by water consist chiefly of minerals and gases. The most common minerals present are calcium carbonate, or limestone; magnesium carbonate, or dolomite; calcium sulfate, or gypsum; magnesium sulfate, or Epsom salts; sodium sulfate, or Glauber's salts; sodium chloride, or common salt; silica, or sand; with minor quantities of iron, aluminum, and others. In the vicinity of mines, water sometimes contains considerable acidity, and in some alkali districts, considerable sodium carbonate, or natural soda ash. The carbonate rarely exists as true carbonate, but rather as bicarbonate, which is a union between the true carbonates, carbon dioxide and water.

The calcium and magnesium bicarbonates and sulfates, and silica are usually classed as scale forming solids present in water. The carbonates will form scale in pipe lines and water heaters even when temperatures are not very high. Sulfates and silica form scale in boilers. The carbonates do not always form scale but may separate out as a sludge or mud.

Corrosion is more commonly caused by dissolved gases naturally present in the water supply, namely, carbon dioxide and oxygen. High quantities of sodium chloride and sodium sulfate tend to accelerate corrosion. Waters having a high ratio of chloride and sulfate to alkalinity are usually corrosive.

Resin is a bead-like plastic or synthetic resin material having ion exchange properties. It is produced from styrene and divinylbenzene and contains sulfonic acid groups. When regenerated with sodium chloride (common salt), it will soften water by exchanging sodium ions for calcium and magnesium ions (hardness). This product, also known as Nalcite HCR**, is widely used as the chemical softening agent in domestic, industrial and municipal water softening equipment.

**Nalcite and HCR are registered trademarks of Nalco Chemical Company.

As the water passes through a water softening appliance containing a bed of resin, the hardness (calcium and magnesium) present in the water is exchanged or swapped for sodium in the resin. When the available sodium has all been exchanged for calcium and magnesium, hard water is present in the softener outlet and the resin must be regenerated. Common salt is used to replenish the supply of sodium in the resin and the hardness is flushed to waste.

Iron in solution is removed in the same manner as hardness. Oxidized iron, or iron in suspension is filtered from the water by the resin. Some iron which may have been in solution when removed by the resin may become oxidized. This form of iron is more difficult to remove from the mineral bed.

If all the iron could be kept in solution before softening, and further oxidation is prevented, large amounts of iron could be removed before leakage would occur. The hardness of the water has a bearing on the amount of iron that can be handled, since this controls the gallons softened between regenerations. Generally, the higher the hardness the greater the amount of iron that can be handled. It is sometimes necessary to limit the amount of water softened between regenerations in order to control the total amount of iron introduced to the resin between regenerations. This is often true when softening low hardness waters containing iron.

Resin is not harmed by hot water. It is widely used in industry at temperatures to 250’F. Not all equipment however, is designed for use with hot water.