THE BUSINESS WITH THE FEAR OF LIME
THE BUSINESS WITH THE FEAR OF LIME
Lime does not enjoy great popularity. Lime occurs naturally in water and contributes significantly to its taste. Visually, lime looks like whitish deposits and does not necessarily correspond to our aesthetic ideas. Manufacturers of water softening systems (also called decalcification systems) therefore advertise the need to reduce lime in the water and suggest a lime danger. However, disadvantages of these systems are not communicated. So when is decalcification useful at all and when should one rather look for alternative methods?
What is lime anyway?
When rainwater seeps into the soil, it enriches itself with various minerals. Since the soil of each region is different, the taste and hardness of the water also varies. If the soil consists of sand and limestone, hard water is more likely to occur. Regions with granite, gneiss or basalt have softer water.
More precisely, lime or limestone is an ionic compound of the elements calcium, carbon and oxygen, which occur naturally in various forms. Normally lime is found in dissolved form in water, as calcium hydrogen carbonate (Ca(HCO3)2). Only when water is heated above 50-60 °C does the carbon dioxide (CO2) content decrease, resulting in the formation of hard calcium carbonate (CaCO3), also known as lime, which is not soluble in water.
Although a high lime content is not the criterion for increasing water hardness, it does contribute to it. The minerals calcium (Ca) and magnesium (Mg) are responsible for water hardness. The more calcium and magnesium in the water, the higher the degree of hardness.
In Germany, the degree of hardness is measured in °dH and divided into three levels:
soft 0-8.4 °dH
medium 8.4-14 °dH
hard > 14 °dH
The lime problem
So as soon as water is heated, lime is no longer soluble in water and adheres to appliances or pipes as a visible white deposit. Under certain circumstances, appliances can then be damaged and their performance impaired. Here, manufacturers of decalcification systems try to advertise their products as salvation for water treatment and promise lime-free and soft water that saves energy and costs. On the surface, this may be true, but really lime-free water is only needed by very few devices. Especially the physical level of lime and possible disadvantages of conventional decalcification are neglected in the evaluation.
The structure of lime
Lime does not generally deposit on appliances and water containing lime does not necessarily taste hard. The explanation lies on the physical level of crystallization, i.e. the structure of lime. In naturally flowing water, the structure corresponds to microscopically fine sand (argonite). This is why natural spring water tastes velvety soft, even with a higher lime content. However, if water is pressed through rectangular pipe systems at high pressure, the lime structure changes to needle-sharp calcite. This form makes lime really aggressive and deposits on pipes and appliances over time, and the water also tastes unpleasantly rough.
Calcite structure
Argonite structure
The handling of lime when using equipment
The pointed lime deposits stubbornly on appliances and pipes over years and can damage them or impair their effectiveness. Here the structure of the lime can be converted back to finer argonite with alternative lime converters. With this structure lime is simply washed out and no longer deposits on appliances and pipes. Even existing deposits are gently removed again. The advantage of these technologies is that they are completely maintenance-free and the chemistry and taste of the water are not changed.
With limescale-sensitive devices, descaling is absolutely necessary to protect them from wear and tear and defects. Often modern devices offer the possibility to fill in preparations against lime directly at the device. Many manufacturers also offer suitable decalcification systems, which can be purchased in combination with their appliances and installed directly in front of the appliance. One advantage of this decentralised type of descaling is that manufacturers of limescale-sensitive appliances often reject warranty claims on the grounds that sufficient descaling has not taken place. By using a separate decalcifying unit directly in front of the appliance, which in the best case is also installed by the manufacturer, it is much easier to take over servicing. In addition, since there is rarely sufficient capacity utilisation of expensive decalcification systems installed in the central water supply, this type is much more cost-effective in most cases. In addition, the degree of hardness can be adjusted more precisely in this way, analogous to the corresponding device. The only disadvantage is a higher planning effort and the maintenance of several small devices.
To be able to decide whether descaling or lime conversion is the right decision, it must first be clarified whether the equipment used is incompatible with lime or whether the structure is decisive.
Devices sensitive to lime
(alternative lime conversion recommended)
Washing machines
Fittings
House pipes
Hot water storage tanks
Devices incompatible with limescale
(descaling recommended)
Coffee machines
Dishwashers
Steam cookers
Technical equipment in medical practices and laboratories
(Central) softening plants
Softening plants, also known as decalcification plants or lime filters, actually originate from the industrial sector, since cost-intensive machines are used there that have to be protected against calcification. Here a huge new market worth billions was opened up by convincing private households of the advantages of these devices as well.
The most common method of softening plants is the chemical ion exchange process. This technical term makes it clearer what actually happens here: Something is exchanged, namely hard calcium ions (Ca+) for softer sodium ions (Na+), also called re-hardening. The principle is simple: artificial resins are charged with sodium ions and exchange these for calcium ions in a defined ratio when water flows through them. After some time, the resin is exhausted and must be regenerated. This is done with simple common salt (NaCl).
Sodium
Nowadays, a low-sodium diet is generally recommended because we already consume too much sodium through our diet and excessive sodium consumption can lead to diseases such as high blood pressure, osteoporosis and even heart failure. According to WHO information, adults should consume a maximum of 2 g of sodium per day. A low-sodium diet even has a maximum sodium intake of 1.2 g per day.
To be able to prepare baby food with water, the limit value of sodium is 20 mg/l. The limit value for low-sodium water, on the other hand, is 100 mg/l. However, the Drinking Water Ordinance (TrinkV), which is responsible for our tap water, sets a limit of 200 mg/l. If the drinking water is now artificially softened, the sodium content in the water increases. To reduce each 1 °dH per litre, 8.2 mg sodium is added to the water. Normally, water with a hardness level above 14 °dH is softened. The aim is usually a degree of hardness of maximum 8 °dH. In this case, 57.4 mg sodium (7 x 8.2 mg/liter) per liter would be added in addition to the existing sodium content.
Taking Berlin as an example, with an average hardness of 17 °dH and a sodium content of 40 mg/l, a softening plant can achieve a value of 113.8 mg/l.
Softening the water by means of an ion exchange process means that the limit value for baby food is generally exceeded and the water is unsuitable for baby food. In most cases, the limit value for low-sodium nutrition is also exceeded. This could lead to problems especially for risk groups. In our opinion, if a central decalcification system is operated in the house, it should be publicly displayed what sodium concentration the water has and that it may no longer be suitable for babies.
Apart from the health disadvantages, sodium also seriously impairs the taste of the water. Since a central decalcification system affects the entire water balance, the increased sodium value changes the taste of food and beverages. This is why complaints about the taste of the water after installation of a decalcification system are more frequent and people switch back to bottled water.
Hygiene risk
Also the danger of a germination is usually not considered. One should bear in mind that the refill container for the salt required for regeneration is an open point in the water network. The regenerating salt is usually delivered in large bags or bought in a DIY store. These are then stored in the cellar for months and are cut open and poured into the containers as required. In this case, meticulous hygiene would actually be advisable, because there is a risk that dirt and germs could get directly into the water of the house. It is also important to ensure proper maintenance, as otherwise there is an increased risk of germs. The drinking water would be hygienically impaired and no longer edible.
Environmental pollution
Softening plants may have the reputation to make an ecologically valuable contribution. However, considerable doubts are appropriate here as well. Unnecessarily, additional salts get into the groundwater through the ion exchange. This is because the regeneration water resulting from the exchange is not clarified by the plant and is thus flushed into the groundwater. In addition, water consumption increases because the plants also need more water for flushing. This is why the Federal Environment Agency also considers water softening plants to be of little use.
A wise investment?
In principle, even the ion exchanger cannot ensure that disturbing deposits on showers, wash basins and fittings are no longer visible. On the one hand these deposits consist of a mixture of shampoo residues, body fat and various minerals and on the other hand a decalcifying system only takes the calcium out of the water, but not the other minerals, which also lead to deposits.
On the other hand, dissolved lime buffers the carbonic acid in the water and thus stabilises the pH value. It is also responsible for dissolving silicates and phosphates. If the water is too soft, pipes can corrode more easily and it can lead to soap dissolving less easily. For these reasons it is advisable never to soften water completely. Therefore, central decalcification systems, in non-industrial areas, usually only reduce the water up to a hardness of 8 °dH. However, this only delays the appearance of the annoying lime deposits.
Considering the high purchase and maintenance costs of a central decalcification system, this makes little sense, either economically or ecologically, just to have a little less lime deposits on the wash basin. A manual decalcification of a washing machine with citric acid every 6 months, for example, costs approx. 2 euros in comparison and is also environmentally friendly. Mechanisms of bathroom or kitchen fittings cost approx. 15 Euro. Decentralised limescale filters to protect the coffee machine and other sensitive appliances are available for just a few hundred euros.
Especially in the hotel industry, decalcification systems have become strongly established. The investments for this are in the 4-digit range and the maintenance can amount to several thousand Euros per year. However, as all wet areas are cleaned daily by the housekeeping, this investment is usually uneconomical. Not to forget that all food and drinks in the entire hotel are prepared with water with increased sodium levels.
In terms of taste, the lime content changes mainly beverages. Especially for tea and coffee, soft water is preferred. However, tea and coffee experts confirm that minerals in water are extremely important for the taste of coffee and tea. Water with too few minerals is not even suitable. Too much sodium also impairs the taste of tea. Here too, we recommend an alternative limescale treatment, because sensorially swirled water is also very soft and perfectly suitable for use with teas, as tea shops working with our alternative technologies confirm.
Conclusion
As long as the water is used for the preparation of food and beverages, we generally advise against the use of central decalcification systems using ion exchange for health and taste reasons. In our opinion, a clear distinction should be made between water for machines and water for people. Contrary to widespread opinion, lime and hard water is neither unhealthy for the body nor does it lead to arteriosclerosis. Only in the case of kidney diseases should we switch to water low in minerals. Calcium and magnesium are vital minerals for humans. Therefore there is no limit value for lime in drinking water. However, since we cover the main need for magnesium and calcium through our diet and only a fraction of the minerals contained in drinking water are actually metabolized by the body, the hardness of the water remains a question of taste.
Recommendation
In regions with a degree of hardness above 8°dH we recommend physical lime treatment to protect machines and pipes from deposits. The turbulence and vitalization devices from UMH used by LEOGANT, for example, work completely without chemicals, electricity or magnets and are maintenance-free. They ensure a demonstrable structural change in the lime. This prevents lime deposits in pipes and protects them permanently. Old deposits can also be removed gently and a reduction in the amount of detergent and energy required can be determined. The water becomes significantly softer and fresher in taste, without any chemical changes to the water, which is beneficial for cooking, bathing and showering.
To protect sensitive equipment, we recommend decentralised descaling directly in front of the unit. If there are too many individual units in use, which would make a decentralised solution disproportionately expensive, and centralised descaling systems would have to be used, we recommend separating the drinking water from the softened water and laying separate pipes for drinking water and softened water.
If a central water softening system is already installed and this cannot be removed for various reasons, we recommend the installation of a vitalisation system to harmonise the sodium in the water. Furthermore, the maintenance intervals of the softening plants must be strictly adhered to and attention must be paid to hygiene. The target value should not be set below 8°dH in order not to increase the sodium content unnecessarily.
In general, all LEOGANT filter systems can be combined with a decalcification system and their effect is not impaired. Since activated carbon does not filter minerals out of the water, our filter systems also do not remove sodium from the water. Therefore, everyone should decide for himself up to which sodium content the taste of the water is pleasant.
In our opinion, the sodium content should not exceed 100 mg/l and for small children a maximum of 20 mg/l. As long as these values are maintained, the amount of sodium in the water is purely a matter of taste.
If a decalcification system is available, we recommend having the sodium content determined by a water analysis. This value also depends on the natural sodium content and the hardness of the tap water and can therefore vary considerably.
About the author:
Thomas Hartwig is a certified medical nutritionist and founder of the company Leogant. For many years he has been intensively involved with the element of water. He is a valued keynote speaker and guest on podcasts, where he shares his knowledge and experience. In his work he combines findings from natural science and medicine with philosophical approaches to contribute to a holistic water awareness.