How do you measure water quality?

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Updated on: 2020-02-26

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The way to healthy water

Today, consumers seem to have a variety of products available to them to improve the quality of their water. In addition to water filters (osmosis plants), measuring instruments are often used or offered as part of a consultation. But by far not all measuring instruments say anything at all about the quality of water. Before deciding on a water filter system, it is therefore a good idea to find out more about the nature of our water and what, for example, so-called TDS measuring devices actually measure.

Measuring water quality

It is often said that the quality of water can be assessed with the help of the TDS reading. This also means that it is possible to find out whether one's own drinking water is free of pesticides, drug residues and other harmful substances. It is sometimes said that only water with a very low TDS value ( ≤ 100 µS) is beneficial to health.

However, this contradicts both scientific principles and the guidelines of the World Health Organization (WHO). According to these guidelines, a guide value such as that provided by the TDS measuring instruments says nothing about the water quality.
To make a reliable statement about the water quality, a chemical analysis is necessary. The TDS reading provides only a specific indication of the composition of water.

What is measured with a TDS meter?

TDS stands for "Total Dissolved Solids". This means nothing else than that the TDS value indicates the sum of dissolved solids in the water. These include, for example, minerals, salts and metals. The device used for this purpose makes a physical measurement. It determines the electrical conductivity of the water. The degree of this conductivity depends on the ions, the electrically charged molecules, in the water. Conductive materials are mainly salts, minerals and metals. They have an electrical resistance. This can be described by physics in a measured variable.

What is measured with a TDS device

From the measured value of the TDS device to the sum of dissolved solids in water

The electrical conductivity of a substance is specified with the measurand Mikrosiemens (µS). This can be converted into the sum of dissolved conductive particles, either in the common unit mg/l (milligram per liter) or ppm (parts per million). The following conversion key applies: 1.2 µS/cm = 1 ppm = 1 mg/l.

The general informative value of the TDS value

Once you have measured either a µS value or ppm value, you have a quantitative result in your hand. We now know that we have a high or low number of conductive, dissolved substances in the water. These can be, for example, the very minerals that shape the regional character of the water. Minerals belong in natural spring water and form its typical regional flavour. Whether a water has many or few minerals depends solely on the region and is not a general characteristic of its quality.

In fact, the TDS value alone does not provide any information about the purity and water quality, as many harmful and harmful substances cannot be detected by such a physical measurement. These include residues of hormones, pesticides and fungicides.

Limited informative value of TDS values when using osmosis plants

If the TDS value is used as an argument at the beginning of a consultation on the use of water filters, this can be misleading. If the water, the quality of which is to be improved, is passed through an osmosis plant, the proportion of electrical substances decreases. Consequently, a low measured value is shown. In reality, this osmosis water simply contains little or no minerals. If some salt were added to the water, the TDS value would rise immediately. But this would by no means make the water unhealthy. Conversely, for the reasons mentioned above, it has not been proven at all that the water with the low TDS value measured after cleaning is healthier.

What can the TDS value then be used for?

The TDS value can be used to check whether a water filter is working properly or has been connected correctly after the initial setup of the system. Especially in reverse osmosis systems it is often the case that if the filter change is neglected, the water filters become contaminated, which means that pre-filtration no longer takes place and the filter performance is then severely reduced.

Regular checks pay off in lower maintenance costs

If the filter is no longer fully functional, the so-called membrane must compensate for the increased filter power requirement. As a result, the service life of the diaphragm is shortened. In any case, replacing the more expensive membrane is more expensive than changing the filter regularly.

Recommendation: The effective overall solution

Decide for yourself which substances you want in your drinking water! With our Stand Alone Filter you can easily do this in one step - without prior water purification by an osmosis plant. With the Alb Filter drinking water cartridges you get clean and at the same time high quality drinking water, free of toxins, but with valuable minerals and trace elements. In this way you can actually influence the water quality instead of just taking a reading that does not really tell you anything about the quality of your water.

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Total solution Alb Filter. Leaves minerals in drinking water without filtering them