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 exactly is limescale?
When rainwater seeps into the ground, it becomes enriched with various minerals. Since the soil composition varies from region to region, the taste and hardness of the water also vary. If the soil consists of sand and limestone, the water is more likely to be hard. Regions with granite, gneiss, or basalt have softer water.
More precisely, limescale or limestone is an ionic compound of the elements calcium, carbon, and oxygen, which naturally occurs in various forms. Normally, limescale is dissolved in water as calcium bicarbonate (Ca(HCO3)2). Only when water is heated above 50-60 °C, the reduction of carbon dioxide (CO2) forms the hard and insoluble calcium carbonate (CaCO3), also known as limescale.
Although a high limescale content is not the sole 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 present 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 limescale problem
As soon as water is heated, limescale is no longer soluble and adheres to appliances or pipes as visible white deposits. Under certain circumstances, appliances can be affected and their performance impaired. Here, manufacturers of descaling systems try to promote their products as saviors of water treatment, promising limescale-free and soft water that saves energy and costs. On the surface, this may seem to be the case, but truly limescale-free water is only needed by very few appliances. In particular, the physical aspect of limescale and potential disadvantages of conventional descaling are often neglected in the assessment.
The structure of limescale
Limescale does not generally deposit on appliances, and water containing limescale does not necessarily taste hard. The explanation lies in the physical level of crystallization, i.e., the structure of the limescale. In naturally flowing waters, the structure corresponds to microscopically fine sand (Argonite). Therefore, natural spring water tastes velvety smooth even with a higher limescale content. However, when water is forced through right-angled pipe systems under high pressure, the limescale structure changes to needle-pointed calcite. This form is what makes limescale truly aggressive, causing it to deposit on pipes and appliances over time, and the water also tastes unpleasantly rough.
Calcite structure
Argonite structure
Dealing with limescale when appliances are used
Over the years, sharp-edged limescale stubbornly deposits on appliances and pipes, potentially damaging them or impairing their function. Alternative limescale converters can transform the limescale structure back into finer aragonite. This structure allows limescale to be easily flushed away, preventing further deposits on appliances and pipes. It even gently removes existing deposits. The advantage of these technologies is that they are completely maintenance-free and do not alter the chemistry or taste of the water.
For limescale-sensitive appliances, descaling is essential to protect them from wear and defects. Modern appliances often offer the option to add anti-limescale products directly into the device. Many manufacturers also offer suitable descaling systems that can be purchased in combination with their appliances and installed directly in front of them. One advantage of this decentralized descaling method is that manufacturers of limescale-sensitive appliances often reject warranty claims, arguing that adequate descaling has not been performed. By using a separate descaling system directly in front of the appliance, ideally installed by the manufacturer, service acceptance is much easier. Additionally, since expensive descaling systems installed in the central water pipe are rarely used to their full capacity, this method is often more cost-effective. It also allows for more precise adjustment of the hardness level, similar to the corresponding appliance. The only disadvantage is the increased planning effort and the maintenance of multiple small devices.
To decide whether descaling or limescale conversion is the right choice, it must first be clarified whether the appliances used are limescale-intolerant or whether the structure is the decisive factor.
Limescale Structure-Sensitive Appliances
(Alternative limescale conversion recommended)
Washing machines
Faucets
House pipes
Hot water tanks
Limescale-Intolerant Appliances
(Descaling recommended)
Coffee machines
Dishwashers
Steam cookers
Technical equipment in medical practices and laboratories
(Central) Softening Systems
Softening systems, also known as descaling systems or limescale filters, originally came from the industrial sector, where they are used to protect expensive machinery from calcification. A huge new market worth billions was created by convincing private households of the benefits of these devices.
The most common method used by softening systems is the chemical ion exchange process. This technical term clarifies what actually happens: something is exchanged, namely hard calcium ions (Ca+) for softer sodium ions (Na+), also known as re-hardening. The principle is simple: synthetic resins are charged with sodium ions and exchange them for calcium ions in a defined ratio as water flows through them. After some time, the resin is exhausted and must be regenerated. This is done with simple table 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 data, 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 prepare baby food with water, the limit for sodium is 20 mg/l. The limit 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, specifies a limit of 200 mg/l. If the drinking water is artificially softened, the sodium content in the water increases. For the reduction of every 1 °dH per liter, 8.2 mg of sodium are added to the water. Water with a hardness level above 14 °dH is usually softened. The goal is usually a hardness level of maximum 8 °dH. In this case, 57.4 mg of sodium (7 x 8.2 mg/liter) would be added per liter in addition to the existing sodium content.
Using Berlin as an example, with an average hardness level of 17 °dH and a sodium content of 40 mg/l, a softening system would result in a value of 113.8 mg/l.
With water softening using the ion exchange process, the limit for baby food is therefore fundamentally exceeded, and the water is unsuitable for baby food. In most cases, the limit for a low-sodium diet is also exceeded. This could lead to problems, especially for risk groups. In our opinion, if a central descaling system is operated in the house, the sodium concentration of the water should be publicly posted, along with a warning that it may no longer be suitable for infants.
Apart from the health disadvantages, sodium also significantly worsens the taste of the water. Since a central descaling system affects the entire water supply, the increased sodium level changes the taste of food and drinks. Therefore, complaints about the taste of the water often arise after the installation of a descaling system, and people switch back to buying bottled water.
Hygiene risk
The risk of contamination is also usually not considered. Keep in mind that the refill container for the salt needed for regeneration is an open point in the water network. The regeneration salt is usually delivered in large sacks or bought at the hardware store. These are then stored in the basement for months and cut open and poured into the containers as needed. Strict hygiene would actually be appropriate here, because there is a risk that dirt and germs will get directly into your house water. Proper maintenance must also be ensured, as there is otherwise an increased risk of germs. The drinking water would be hygienically impaired and no longer potable.
Environmental impact
Softening systems may have the reputation of making an ecologically valuable contribution. However, there are considerable doubts about this as well. Unnecessarily, additional salts enter the groundwater through the ion exchange. This is because the regeneration water produced during the exchange is not clarified by the system and is therefore flushed into the groundwater. In addition, water consumption increases because the systems also require more water for rinsing. For this reason, the German Environment Agency also considers water softening systems to be of little use.
A worthwhile investment?
In principle, even the ion exchanger cannot ensure that no disturbing deposits are visible on showers, sinks and fittings. On the one hand, these deposits consist of a mixture of shampoo residues, body fats and various minerals, and on the other hand, a descaling system only removes the calcium from the water, but not the other minerals that also lead to deposits.
On the other hand, dissolved lime buffers the carbonic acid in the water and thereby stabilizes the PH value. It is also responsible for the dissolution of silicates and phosphates. If the water is too soft, pipelines can corrode more easily and it can lead to soap dissolving less well. For these reasons, it is advisable never to completely soften water. Therefore, central descaling systems in the non-industrial sector usually only reduce the water to a hardness level of 8 °dH. However, this only delays the occurrence of annoying limescale deposits.
Considering the high acquisition and maintenance costs of a central descaling system, it makes little economic or ecological sense to only have slightly fewer limescale deposits on the sink. Manual descaling of a washing machine with citric acid every 6 months, for example, costs about 2 euros in comparison and is also environmentally friendly. Mechanisms for bathroom or kitchen faucets cost about 15 euros. Decentralized limescale filters to protect the coffee machine and other sensitive devices are available for just a few hundred euros.
Descaling systems have become particularly well established in the hotel industry. The investments for this are in the 4-digit range and maintenance can cost several thousand euros annually. However, since all wet areas are cleaned daily by housekeeping, this investment is usually uneconomical. Not to mention that all food and drinks in the entire hotel are prepared with water with increased sodium levels.
The calcium content primarily alters the taste of beverages. Soft water is generally preferred, especially for tea and coffee. However, tea and coffee experts confirm that minerals in the water are extremely important for the taste of coffee and tea. Water with too few minerals is not suitable at all. Too much sodium also impairs the taste of tea. Here too, we recommend an alternative calcium treatment, because from a sensory perspective, swirled water is also very soft and ideally suited for use with teas, as confirmed by tea shops that work with our alternative technologies.
Conclusion
As long as the water is used for preparing food and beverages, we generally advise against using central softening systems that use 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 popular belief, calcium and hard water are neither unhealthy for the body nor do they lead to calcification of the arteries. Only those with kidney disease should switch to water with low mineral content. Calcium and magnesium are essential minerals for humans. Therefore, there is no limit value for calcium in drinking water. However, since we cover our 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 matter of taste.
Recommendation
In regions with a hardness level above 8°dH, we recommend physical calcium treatment to protect machines and pipes from deposits. The swirling and revitalization devices from UMH used by LEOGANT, for example, work completely without chemicals, electricity or magnets and are maintenance-free. They ensure a demonstrably structural change in the calcium. This prevents calcium from depositing in pipes and protects them permanently. Old deposits can also be gently removed, and a reduction in detergent and energy consumption can be observed. The water tastes significantly softer and fresher, without any chemical alteration of the water, which has a positive effect when cooking, bathing and showering.
To protect sensitive devices, we recommend decentralized softening directly in front of the device. If too many individual devices are in use, which would make the costs of a decentralized solution disproportionately high, and central softening systems have to be used, we recommend separating the drinking water from the softened water and installing separate lines for drinking water and softened water.
If a central softening system is already installed and cannot be removed for various reasons, we recommend connecting a revitalization unit downstream to harmonize the sodium in the water. Furthermore, the maintenance intervals of the softening systems must be strictly observed and hygiene must be ensured. The target value should not be set below 8°dH in order not to unnecessarily increase the sodium content.
In general, all LEOGANT filter systems can be combined with a softening system and their effectiveness is not impaired. Since activated carbon is known not to filter minerals out of the water, sodium is also not removed from the water in our filter systems. Therefore, everyone should decide for themselves 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 should be a maximum of 20 mg/l for small children. As long as these values are maintained, the amount of sodium in the water is purely a matter of taste.
If a softening system is present, we advise 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 greatly.
About the author:
Thomas Hartwig is a certified nutritional advisor and founder of LEOGANT. He has been working intensively with the element of water for many years. He is an esteemed keynote speaker and guest on podcasts, where he shares his knowledge and experience. In his work, he combines insights from natural science and medicine with philosophical approaches to contribute to a holistic water awareness.