Water is the source of life, people can not live without water. Have you ever experienced that bottled water tastes different from tap water, which is soft and easy to drink, while some tap water is heavy and bad to drink.
In fact, that is the difference between soft water and hard water, because tap water is not softened, the concentration of minerals in the water is very high, resulting in the water is hard, and the quality of bottled water after processing has become soft, more suitable for people to drink. But what’s the detailed difference between hard water and soft water, and how do you turn hard water into soft water?
What are hard water and soft water?
Soft water: Water without or containing less soluble calcium and magnesium compounds. In natural water, rain, snow, and distilled water are soft.
Hard water: Water that contains more soluble calcium and magnesium. Identification and distribution of soft water and hard water. When used at home, the water not only lathers the soap but also deposits a layer of scale on the laundry. When boiling water, a layer of hard white scale gradually forms on the bottom of the kettle and the bottom of the thermos bottle.
At present, the water hardness of different countries, such as the United Kingdom less than 50 mg/L of calcium carbonate is soft water, while in the United States less than 60 mg/L of calcium carbonate water is classified as soft water.
The difference in taste
Soft Water: Because the amount of calcium and magnesium is small, the taste is soft, suitable for making tea, coffee, cooking. Because magnesium content is low, so also suitable for the preparation of baby milk powder.
Hard water: The amount of calcium and magnesium, in general, the more minerals, taste astringent and heavy sense of the stronger.
How soft and hard water are formed？
In the natural circulation, rainwater is distilled water formed by nature, which contains very few minerals and is highly soluble. After falling on land, it is scoured by soil and seeped into the ground to participate in the formation of sedimentary rocks. Calcium and magnesium ions, the two main ions in water hardness, are found in many sedimentary rocks, the most common of which are limestone and dolomite.
From the river water hardness map can be found, most of the rainfall areas and near the source of glacier water, low hardness, for natural soft water.
How to distinguish soft water from hard water?
- Method 1: Take a cup of hot water, cut up the soap into it, if the soap can completely dissolve, cooling into a translucent liquid, that is soft water; if the water surface after cooling has a layer of undissolved foam is hard water. The more foam, the harder the water.
- Method 2: Heat a container full of water. If there is more scale on the inside of the container after heating, it is hard water. Because hard water is containing more soluble calcium, magnesium material water, after heating, these soluble calcium and magnesium material into insoluble material, precipitation impurities are more hard water, the more impurities, the hardness of the water.
- Method 3: Dip two dry clean towels into hard water and soft water, wring out, wipe the lenses and dry them. If there is water on the lens is hard water, if there is no water on the lens and bright as new is soft water.
- Method 4: Ice Cubes were made with soft water and hard water respectively. As calcium carbonate and magnesium carbonate are insoluble in water, the ice cubes made with hard water can be observed to have turbid colors and peculiar smells. The ice cubes made with soft water are crystal clear and soft to the touch.
Is it safe to drink hard water?
Hard water is generally safe to drink.
According to the World Health Organization: there is no convincing evidence that it is harmful to the human body. In fact, hard water may be beneficial to human health, it can be used as the body needs a variety of minerals such as magnesium, calcium, and dietary supplement, in addition, hard water on cardiovascular, osteoporosis, and other diseases can also play a very good preventive role.
Hard water is good for you, but soft water is even better. In addition, hard water can cause some inconvenience to human life.
Influence of water hardness on home life
- When the water hardness is more than 200mg/L, there will be some precipitation in the cold water pipe network.
- When the water hardness is less than 100 mg/L of soft water, will increase the corrosion of metal pipes.
- In heating equipment, deposited scale impairs heat transfer between water and heating elements, reduces heating efficiency, and may cause heating elements to overheat, damage, or shorten their life (e.g. coffee machines are clogged with scale build-up), making cleaning more difficult.
- In a pressurized heating system, a layer of hard calcium sulfate or silicon dioxide, or soft calcium carbonate scale may form on the bottom of the electric water heater or boiler and the pipe wall, which may block the pressure relief valve and cause the pipe wall to overheat and deform, that caused the boilers and pipes to explode.
- For domestic use, hard water not only does not lather the soap but also deposits a layer of scale on the laundry. When boiling water, a layer of hard white scale gradually forms on the bottom of the kettle and the bottom of the thermos bottle.
Effects of water hardness on human health
The World Health Organization recommends maximum and minimum levels of calcium (40-80 ppm) and magnesium (20-30 ppm) in drinking water. Total hardness is expressed as the sum of 2-4 mmol/L calcium and magnesium concentrations. In addition, the high hardness of the water in the home may lead to early infant eczema.
|Standard||Limit mg/L (CaCO3)|
|Standard for drinking water in China||< 450|
|WHO guidelines for drinking water quality||< 500|
|Standard for drinking water in Japan (1993)||< 300|
|European community regulations on drinking water||< 60|
|China's clean drinking water (Urban Construction Industry Standard)||< 300|
Drinking water with a hardness of 150- 450 mg/L is most beneficial to human health, experts suggest.
How to soften the hard water？
Although a certain hardness of water can reduce metal toxicity and the incidence of cardiovascular disease, the residents of drinking water also need to be softened to avoid the adverse consequences of hard water.
So how do you turn hard water into soft water? At present, there are distillation and boiling methods on the market, but some of these methods can only kill bacteria, some can remove bacteria, microorganisms, and suspended solids, and some can even remove all the minerals and become so-called pure water, long-term drinking on the human body there are safety risks.
1. Pre-water purification equipment
Generally installed in the front of the pipeline, filtering can effectively remove water sediment, rust, bacteria, colloids, macromolecular organic substances, and other harmful substances, retain beneficially to the human body minerals and micronutrients.
Advantages: It can effectively filter the harmful substances such as silt, rust, bacteria, colloid, macromolecule organic matter in water, effectively protect and prolong the life of household water-wading electric appliances, generally the price is cheaper, and won’t have the trouble of changing the filter element, it usually lasts 5-10 years, maybe longer.
Disadvantages: Filtering accuracy is not high, mainly coarse filtering, the need for regular washing filter. The prepositive water purifier is the most commonly used filter in the home and can be used with other softening equipment. Germany introduced legislation in 1989 requiring all buildings after 1988 to be fitted with front-mounted filters.
2. Reverse osmosis equipment
Reverse osmosis is a pressure-driven membrane separation technique with the aid of selective (semi-permeable) membrane function, when the pressure applied in the system is greater than the osmotic pressure of the inlet solution, the water molecules pass through the membrane through the water-producing channel and flow into the central pipe. The impurities in the water, such as ions, organic matter, bacteria, and viruses, are trapped in the inlet side of the membrane, and then flow out at the outlet end of the concentrated water, in order to achieve separation and purification purposes.
Advantages: The reverse osmosis water purifier can not only remove impurities, rust, colloids, bacteria, viruses but also remove harmful radioactive particles, organic matter, fluorescents, pesticides, as well as unpleasant water alkali and heavy metals, when boiling water to ensure that there is no water alkali, to ensure the health of the family.
Disadvantages: Reverse osmosis water purifier out of the water is too pure, drinking for many years easy to lead to the loss of minerals in the body, especially human calcium ion and osteoporosis.
Reverse osmosis (Ro) is a POU (terminal) equipment in home and catering, which is mainly used in beverage preparation, cooking, and drinking due to its high cost and low water-making efficiency.
3. Lon-exchange resin
Lon-exchange resin is a chemical used primarily in the manufacture of refined sugars and the purification of high-grade edible syrups. Ion-exchange resins are generally porous or granular in shape, with sizes ranging from 0.5 mm to 1.0 mm.
Advantages: Ion-exchange resin has many advantages, large flow, regeneration resin through sodium chloride, economic and efficient, inorganic ion removal capacity is excellent. The utility model has the advantages of regeneration ability and simple device.
Health risk: The regenerant is sodium chloride, which causes an increase in the sodium content of the softened water.
Environmental risks: The State of California enacted Act No. 1366 to ban the installation of water softeners that use sodium, potassium, or chloride due to concerns about the release of salt into the environment during the regeneration of traditional water softeners, and drain the salt solution down the drain.
Lon-exchange resin is commonly used in homes and restaurants and is commonly referred to as a water softener.