Translating…
Most people are not sure if they have hard water or not. A few signs of hard water in your home are mineral deposits in toilets and sinks, clogged shower heads and furred taps. There is sometimes residue on glasses after washing and mineral stains on laundry.
Hard water is caused by the presence of magnesium and sodium ions in the water. Hard water clogs pipes and it does not form lather with soap so laundry becomes a problem. The process of softening hard water is called water softening and involves removal of the calcium and magnesium ions and replacing with sodium.
There are two approaches to softening water; you can either treat the water supply to whole house by softening the water at the point of entry or by doing it at the point of use, for example at the kitchen sink by means of an in-line water filter. Among the two, a whole house water softening system makes more sense as it treats the whole house including the central heating system which can save on energy use and repair bills.
Water can be softened by a number of different processes. Simple carbon water filters are probably the simplest method to protect individual appliances and improving the taste of the drinking water at the same time. However these need replacing regularly which can be inconvenient.
Salt based water softeners are usually the best solution for the home. There are other treatment methods such as reverse osmosis and de-mineralization units but these are mainly used on commercial premises.
Electric and magnetic softeners are a bit of a novelty. They are meant to discourage the formation of scale as the water passes through the system for a limited period due to the magnetic or electrical effects of the magnets. Despite being sold the world over, the effectiveness of these devices is limited at best.
For most households the use of a salt based water softener will give great results and soften the water throughout the entire house. Sinks and taps will stay shiny, shower heads will be clear of scale and water will lather easily. The savings made by using less soap, detergent and cleaning materials can often pay for the softener within a few years. In addition, heating elements in washing machines, dishwashers and central heating systems will be free of scale improving improving efficiency, resulting in lower energy bills. Maintenance and repair bills will also be substantially reduced.
The capacity of the softener will need to match the estimated volume of water used by the people in the home. Usually the softener unit is installed close to the main stop cock, normally located in the kitchen. Most installers will ensure the main cold water kitchen tap is left un-softened but the feed to the rest of the house is softened. This way drinking water for food preparation is unaffected by the softening system.
The only ongoing costs for a water softener are replacement salt cubes and electricity. The units are generally very reliable and engineer call outs for problems are rare.
Your local softener supplier should be able to recommend the best unit for your home.