We often hear the acronym TDS (Total Dissolved Solids) and how important it is to maintain the right levels in drinking water. Many water purifiers claim to remove this TDS and make the water fit for consumption. Before we dig deep into TDS-related discussion, let us first understand the basics.
What Is TDS?
TDS is a measure of the total concentration of dissolved substances in water. It includes the inorganic salts present in a suspended state in water and organic matter primarily in small amounts.
The inorganic salts commonly present in water are sodium, potassium, magnesium and calcium, which are essential for the body in low concentration. But, nowadays toxic salts like lead and arsenic are also found in water which, if consumed, are detrimental for health. Thus, to get rid of these dissolved chemical contaminants, an RO water purifier is required.
How Do These Chemicals Get Dissolved in Water?
These minerals originate from a variety of sources. They can get dissolved in the water right at origin or when water flows through a region having rocks with high salt content. The salts also get disbanded as a result of human activities like industrial wastewater, agricultural activities, sewage and urban run-off. The water gets contaminated with chemicals all through its journey from the origin to its final destination.
TDS Levels and Water Quality
The body requires some quantity of essential minerals. Ripping off the water entirely of the TDS is not recommended. Here are the various TDS levels and their impact.
# Less than 300 mg/litre: If the water reaching your taps contains a TDS of less than 300 mg/litre, it is considered excellent for consumption. It is because this reading indicates that the required minerals that are essential for the body are present in this water. Water with this TDS level does not have any adverse effect on health or appliances.
# Between 300 and 600 mg/litre: This level is also acceptable, and you don’t need to worry much.
# Between 600 and 900 mg/litre: If the TDS level lies between 600 and 900 mg/litre, having an RO water purifier with TDS controller installed is advisable.
# Between 900 and 1200 mg/litre: The water quality is poor and having an RO purifier with TDS controller becomes a mandatory requirement.
# More significant than 1200 mg/litre: This level of TDS in water is unacceptable, and one needs to install a water softener too besides an RO purifier. Having a softener will ensure that the life of various appliances and pipes in your home is enhanced.
What Happens If TDS Concentration Is Extremely Low or High?
Deficient TDS concentration in water is also unacceptable because it means all the essential minerals are ripped off from water. These minerals are required for the proper functioning of the body. The water tastes flat and stale.
The higher TDS concentrations and that too of toxic elements like mercury, lead and cadmium is more of a concern. These toxic salts are detrimental to health and can even cause diseases like cancer, coronary heart diseases and cardiovascular diseases. The high concentration of salts in water makes it hard, and hard water causes excessive scaling. Thus, the life span of your appliances like heaters, washing machines, geysers and boilers and water pipes gets shortened.
Hard water also causes skin and hair problems. It happens because the extra salts present in water clogs the skin pores. As soap cannot dissolve and form lather in hard water, these salts cannot get washed off. Even the clothes do not get cleaned properly in hard water and appear faded, dull and scratchy because the new mineral substance from tap water remains stuck on the garments. The detergent cannot wash it off because of the lack of lather formation. The utensils and sinks that you wash using this water that has high TDS concentration develop stain marks. The faucet holes also get clogged over time.
If the water has high levels of TDS, it even leads to difficulty in cooking as the food cooked in such water loses on both colour and flavour, and some of the vegetables become tough and shrivelled.
How to Measure TDS Levels in Water?
Now that we know the impact of high TDS levels on health and appliances, we need to understand how to measure the TDS levels in water reaching our homes. Here are some standard methods of doing it.
# Digital TDS Meter
Using a digital TDS meter is one of the most natural methods of measuring the TDS levels in the water. You can purchase a TDS meter, which costs just a few hundred rupees. Measuring TDS is simple using this machine. You need to turn on the meter and then submerge it to a depth of max two inches in the water. If you find any air bubbles, then stir the TDS meter to remove them. In a few seconds, the TDS reading will get displayed on the device. Let it stabilise for a few more seconds and you are done.
# Scale and Filter Paper
It is the conventional way of measuring TDS. To measure TDS following this method, you require the water sample to test, evaporating dish, sterilised beaker, pipette, weighing scale and filter paper. It is a slightly elaborate method, and you need to take the readings accurately. Please start the process by measuring the empty evaporating dish’s weight in milligrams and label it as A. In a beaker, take the sample of water that you want to test for TDS and mix it vigorously so that it gets agitated. This stirring facilitates the even distribution of particulate matter in water.
Take 50ml of this water in a pipette and let it pass thrice through the filter paper. After it gives, transfer the residue you find on the filter paper to the evaporating dish and leave it to dry. Once the waste is dried, measure the weight of the dish again and label the reading as B. You can now calculate the TDS level by using the formula [(A-B) *1000]/ml. Since we used 50ml of water, the ml in the method is to be taken as 50.
You can follow any of the above methods to evaluate the TDS level of the water coming to your home. The first method is quick and easy, while the second method is quite elaborative. Once you know the TDS levels, you can decide on whether or not you would require an RO purifier. If you need to install one, compare various RO water purifiers based on their features, price etc, to find the most appropriate one for your use.
How Does an RO Water Purifier Maintain the TDS Level?
The conventional filters can only remove the physical and biological contaminants. It is because the ordinary fine filter is capable of removing particles up to 0.45 microns in size. The charged atoms and ions are left behind, and they dictate the TDS value. To get rid of these chemical contaminants, you need an RO water purifier.
The problem comes if you use a standard RO purifier without a TDS controller. This purifier filters out most of the dissolved salts from water without differentiating between the essential and non-essential salts. The vital minerals that are required by the body also get eliminated. Consuming water that is ripped off the essential minerals on a prolonged basis leads to many health problems as the body doesn’t get the supply of required minerals. The solution to this problem is provided by technology in the form of an RO water purifier with an inbuilt TDS controller. Such an RO purifier is equipped to dole out filtered water with a TDS level between 50 and 150, which is considered excellent for consumption.
How TDS Controller Works?
A TDS controller is a small device positioned inside the assembly unit comprising of one water output, two water inputs and a TDS control screw. One of the two water inputs is from the purified water output from the RO membrane. The other water input is from an activated carbon filter if you are using the RO+UV+TDS controller or UF Membrane in case you are using RO+UF+UV+TDS Controller.
The water output is where the TDS controller mixes these two water inputs in the desired ratio. This ratio is set using the TDS control screw by adjusting the water flow from the two water inputs. To reduce the TDS, the flow of water from RO membrane input is increased, while the other is decreased and vice versa. For a layperson, the TDS control screw needs to be turned anti-clockwise for increasing the TDS level and clockwise to reduce the TDS level. Thus, buying an RO water purifier with a TDS controller ensures that you get pure and safe water with ideal amounts of TDS present in it.
It is all that you generally need to know about the TDS level in the water. If you find that the water coming to your home contains high TDS concentration, you should invest in a good RO purifier with TDS controller.
