Solutions & Solubility Pure water, which is an odour less, colorless, and tasteless substance is often called the universal solvent. As water moves through soil, it dissolves very small amounts of minerals such as calcium and magnesium. The greater the content of calcium and magnesium, the more hard the water is. Therefore, hard water is the result of an excess of two elements, C and Mg.
The hardness of water is measured in grains per gallon (gig), milligrams per litre (mg / l ) or parts per million (ppm). (See chart below) Grains Per Gallon MiligramsPer Liter (mg / l ) or Parts Per Million (ppm) less than 1. 0 less than 17. 1 Soft 1.
0 - 3. 5 17. 1 - 60 Slightly Hard 3. 5 - 7. 0 60 - 120 Moderately Hard 7. 0 - 10.
5 120 - 180 Hard over 10. 5 over 180 Very Hard You can also detect hard water in your home by examining it for any evidence of film left on your body, the build-up of scale on cooking utensils, clogged pipes, appliances resulting in reduced water flow and increased repairs high in dissolved minerals, specifically calcium and magnesium. Yet although hard water is a nuisance, it poses no health risks. Some of the consequences of hard water include harsh and rough laundry, a film of sticky soap on the skin and faulty operation of water-using appliances such as clogged pipes.
Furthermore, solar heating used for heating swimming pools could be prone to build-up that interferes with the electric pump. Although hard water may interfere with almost every cleaning task, it is still safe for drinking, cooking, and other household uses and may even add to the taste of water, providing a small amount of nutritional benefit. Water softeners, however, may also increases the sodium content in the water, which may pose health concerns regarding a person's intake of sodium. Some of the benefits of softened water include an increase in the life expectancy of the plumbing system, water-using appliances and a reduced soapy residue on clothes, skin, hair, tubs and shower tiles. It will also prevent the scratching of bathroom fixtures as well as sinks and decrease spotting and white chalky deposits, on dishes, pots and pans and glassware. Since the minerals in water give it a characteristic taste, when water is softened it may taste salty and might not be suitable for drinking.
Therefore, soft water may taste bad, but hard water may shorten the life of plumbing and lessen the effectiveness of certain cleaning substances. There are two ways to help control water hardness, adding a packaged or liquid softener to a batch of water, or by using an ion exchange water-softening unit. Powdered or liquid water softeners are chemicals that help control water hardness by removing certain minerals from it. They can be either precipitating or non-precipitating.
Precipitating water softeners include washing soda and borax, which form an insoluble precipitate with calcium and magnesium ions. The mineral ions cannot interfere with cleaning efficiency, but the precipitate makes water cloudy and can build up on surfaces. Precipitating water softeners increase alkalinity of the cleaning solution and many materials being cleaned. Consequently, non-precipitating water softeners use complex phosphates and there is no precipitate to form deposits so therefore alkalinity dies not increase.
If enough quantity is used, non-precipitating water softeners will help dissolve soap and just like precipitating water-softening units can be permanently installed into the plumbing system to continuously remove calcium and magnesium. Hard water can also be softened by treating it with lime or by passing it over an ion exchange resin. In the process of ion exchange water softening, the hardness ions, magnesium and calcium, are exchanged with either sodium or occasionally, potassium ions. This occurs with the flow of hard water over a bed of plastic resin beads where each bead has a slight electric charge. This charge holds the sodium on the bead and as the hardness minerals or ions attach themselves to the beads, the sodium ions are displaced. Therefore, the hardness ions are replaced by the sodium ions.
When the plastic resin beads can no longer be able to remove hardness from the water, brine or salt is used to remove the hardness ions from the beads through the process of regeneration. This salt usually consists of sodium chloride or less commonly potassium chloride. The salt contains a high concentration of sodium ions, which remove the hardness ions from the beads that are then forced out of the resin bed with fresh water.