Water Softener PDF

### What is it's purpose? To soften water. Water is a great solvent, and as it flows through the ground it dissolves a number of naturally occurring minerals, including ones that contain calcium and magnesium. Rainwater is slightly acidic because it interacts with carbon dioxide in the atmosphere...

### What is it's purpose? To soften water. Water is a great solvent, and as it flows through the ground it dissolves a number of naturally occurring minerals, including ones that contain calcium and magnesium. Rainwater is slightly acidic because it interacts with carbon dioxide in the atmosphere to form carbonic acid. This acidity increases the dissolving power of water by allowing it to react with insoluble substances to form soluble ones. Calcium carbonate is a typical case. It occurs naturally as chalk, limestone and marble, all of which are insoluble in water. But when acidic water flows over such deposits, calcium carbonate goes into solution as calcium hydrogen carbonate. This calcium-laced water is what we know as "hard water." It presents several problems. When such water is heated, the soluble calcium hydrogen carbonate breaks down and yields insoluble calcium carbonate. This is essentially the reverse of the formation of hard water and it is what causes scale formation in kettles and hot water pipes. Hard water presents yet another problem. Dissolved calcium reacts with soap to form a precipitate, which we recognize as the "bathtub ring." It also leaves laundry looking grey. One way to reduce water hardness is to run the water through an ion-exchange column which replaces calcium ions with sodium ions.