calcareous, hard water can lead to a variety of problems in everyday life. Limestone stains on faucets and other surfaces in bathrooms and kitchens are quite harmless. But they too get in the way and can get stuck over time, making them difficult to remove. Calcium deposits in household appliances such as boilers, dishwashers or washing machines cause major problems. The water can no longer drain properly, which increases energy consumption and thus the costs of using the devices. As a result, the devices are no longer functional in the long term. To prevent lime, Descaling systems with salt and softening systems without salt, so-called Lime protection systems, popular. While water softening systems with salt are widely used, many consumers are wondering whether and how water hardening systems work without salt. Find out more about the beginnings of descaling systems and learn more about decalcification with and without salt.
First things first: The term descaling plant is not legally protected. Based on the terms descaling plant, water softening system or soft water plant alone, it is often not clear which product or technology is involved. Some products actually reduce water hardness, others leave the amount of lime in the water unchanged. Basically, it can be said that water softening systems with salt (ion exchanger) reduce water hardness - the water becomes softer. Water softening systems or descaling systems without salt, so-called lime protection systems, generally do not result in any reduction in water hardness.
For decades, water treatment has been a process that has been used to make better use of water as a raw material. Over time, various processes have been developed to reduce water hardness. Many of these processes soften the water with salt, and new and innovative ways of operating water softening systems without salt were later developed.
One of the oldest methods for softening water is the lime-soda process. This process was used in the 19th century as part of industrialization. At that time, steam engines were used on a large scale for the first time to drive various types of machinery, such as pumps in mines, textile machines, ships and, last but not least, the steam locomotive. In a steam engine, water was converted into water vapor by heating. If hard water was used for this purpose, lime residues remained in the steam engine, which limited the machine's ability to function in the long term.
To prevent this, the water was first softened using the lime-soda process. Soda, i.e. sodium carbonate, is a salt of carbonic acid which can reduce the total hardness of water to less than 2.0 °dH (German hardness). The lime-soda process was therefore a pioneer of modern descaling systems with salt (ion exchangers), which convert lime using sodium chloride. Then as now, the addition of salts increases the sodium content of the water. This can lead to problems, particularly with drinking water, especially if the sodium content of the water is relatively high even before decalcification. The Drinking Water Ordinance requires a maximum sodium content of 200 mg/l. To the Disadvantages of water softening systems with salt To avoid (ion exchangers), so-called Lime protection systems developed. In this context, people also speak colloquially of water softening without salt.
In order to avoid an increase in sodium in water due to descaling systems with salt, alternatives in the form of softening systems without salt have been designed over time. In many methods of decalcification without salt, so-called seed crystals are to be formed in various ways. These provide a point of accumulation for lime in water so that lime does not settle and is instead rinsed out. It is unclear when and by whom the phenomenon of seed crystal formation was discovered.
There are a number of different methods for forming seed crystals in water. In a study from 2003 by the German Gas and Water Association (1), 4 processes are described which are intended to reduce calcium deposits in drinking water installations without salt:
The first patents for magnetic water treatment were granted in the USA as early as 1873. Water softening systems, which are intended to remove lime through magnetic fields, are equipped with permanent magnets or electromagnetic fields. Electrical impusles are also used. This is intended to change the surface charge of the particles in the water and thus trigger electrolysis processes, which should lead to an excess of OH ions. The ions should create local oversaturation, which should reduce calcium deposits.
In electrochemical methods for softening water without salt, there are various hypotheses as to what extent the forces used can prevent the formation of lime. In general, an undervoltage separation should be produced in water, which produces OH ions, which increase the pH value. The oversaturation should lead to calcium carbonate (CaCO3) precipitation — these precipitated Ca-CO3 crystals become seed crystals, which transport unwanted lime out of the water.
In electrogalvanic lime protection systems, components with a more elegant housing wall and a sacrificial anode made of metal, such as zinc, are installed within the system. The zinc released into the water is intended to serve as a center for the growth of lime crystals.
To protect lime due to heterogeneous catalysis, granules made from special polymers are added to the water. As a result, seed crystals should form on the surface of the polymer, which remove unwanted lime.
The effectiveness of lime protection devices has been or is sometimes described as scientifically disputed. However, there are differences between the individual technologies & processes, so that, for example, effectiveness studies have been available for certain products for several years.
The effectiveness of descaling systems with salt (ion exchangers) is largely not questioned by experts, as the reduction in water hardness (softening) can be proven, for example, with classic hardness measuring tools. However, the above-mentioned study from 2003 by the German Gas and Water Association (1) also makes it clear that certain types of lime protection systems work: For example, there are products in the categories of electrochemical systems and heterogeneous catalysis, which effectively reduce calcium deposits through seed crystal formation. In the area of magnetic and electric field systems, the authors of the study “Drinking Water Purifiers” Wricke and Baumgardt from 2003 point out that at the time the study was published in 2003, only individual effects had been scientifically proven and there are conflicting opinions about the effectiveness of these systems. The authors make a similar statement with regard to electrogalvanic systems.
What the study does not answer is whether descaling systems with salt or softening systems without salt are better. Although water softening systems with salt have been shown to reduce water hardness in order to reduce calcium deposits, there are also lime protection systems without salt, which effectively reduce calcium deposits. It is important in this context that water softening systems with salt have a number of disadvantages, such as an increase in sodium levels and running costs due to regular maintenance. Learn more about the drawbacks here of water softening systems.
Are you faced with the decision whether you should invest in a water softener with salt or a lime protection system without salt? A lime protection system offers you these advantages:
Are you looking for a softening system without salt, are you at AQON PURE at the right address. In our Shop Find the right system for your home right away. Send us one today non-binding offer request and receive a non-binding offer for your salt-free water descaling system from AQON PURE.
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(1) Water Technology Center (TZW), Karlsruhe, Dresden branch office, B. Wricke, W. Baumgardt (2003); study “Drinking water purifiers”: state of the art of alternative systems available on the market to prevent or reduce stone formation in the hot water area
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