What is Reverse Osmosis? How Does a TDS Meter Work?
What is Reverse Osmosis and How Does It Work?
Among water purification methods, Reverse Osmosis (RO) stands out as the most effective and widely used technology. RO water purification systems are becoming increasingly popular worldwide, especially for producing clean drinking water. So, what exactly is reverse osmosis, and how does it work?
What is TDS? What Should the TDS Meter Reading Be in Water Purification?
TDS is one of the most frequently asked questions by water purification device users. Water contains many dissolved organic and inorganic substances that are invisible to the naked eye. The amount and concentration of these dissolved substances in water are measured by the Total Dissolved Solids (TDS) value.
In this article, you'll find detailed information on what TDS values mean, how a TDS meter works, and why it is essential for measuring water quality.
What is TDS?
TDS stands for Total Dissolved Solids, referring to the amount of dissolved substances in water, including magnesium, sodium, potassium, phosphate, calcium, nitrate, chloride, heavy metals, and salts. These substances often come from natural sources, urban pollution, domestic waste, and industrial waste. The higher the TDS value, the lower the taste, smell, and overall quality of the water. Therefore, TDS is a critical indicator of the quality of rivers, lakes, streams, pool water, aquarium water, and drinking water.
TDS Values
TDS is measured in parts per million (ppm) or milligrams per liter (mg/L) and is classified as follows:
- 0–50 ppm: Represents pure water with minimal dissolved solids.
- 50–150 ppm: Ideal for drinking water due to light mineral content.
- 150–300 ppm: High in minerals, suitable for aquariums and plants.
- 300–600 ppm: Contains a high concentration of dissolved substances.
- 600+ ppm: Very high in dissolved substances, unsuitable for drinking.
Common Dissolved Substances in Water
The most common dissolved substances in water include:
- Calcium
- Potassium
- Magnesium
- Aluminum
- Sodium
- Arsenic
- Chloride
- Zinc
- Copper
- Chlorine
- Fluoride
- Sulfates
- BPA (Bisphenol A)
- Lead
What is a TDS Meter?
A TDS meter is a digital device used to measure the concentration of dissolved substances in sources such as spring water, pools, aquariums, and drinking water. The two metal electrodes at the tip of the device measure the water's electrical conductivity, determining the amount of dissolved salts, minerals, heavy metals, and other solutions.
How Does a TDS Meter Work?
The dissolved substances in water create positively and negatively charged particles, increasing the water's electrical conductivity. When the TDS meter's electrodes are submerged in water, they measure this conductivity and calculate the total dissolved solids (TDS) in the water.
How to Use a TDS Meter?
Using a TDS meter is simple:
- Ensure the water temperature is at a low or medium level.
- Rinse and dry the device’s electrodes with clean water.
- Submerge the electrodes into the water to be tested.
- Press the button to start the measurement.
- The device will display the TDS value in ppm or mg/L.
Ideal TDS Value for Water Purification
The ideal TDS value for purified water should be between 50–150 ppm. Water with TDS below 50 ppm may lack essential minerals, while water with TDS above 150 ppm can cause health issues such as bone calcification and kidney problems. Therefore, drinking water should not be consumed if its TDS value is below 50 ppm or above 150 ppm.
For water with TDS levels above 150 ppm, reverse osmosis filtration systems are recommended. Additionally, a mineral filter should be used to prevent the TDS from falling below 50 ppm.
For daily use, the ideal TDS value should be between 0–400 ppm. Water above this range can cause scaling in pipes and appliances, so ion exchange systems, water softeners, or industrial water purification systems are advisable.
The Importance of TDS
While we have explained what TDS is, it’s important to understand its significance. According to the World Health Organization (WHO), the Water, Sanitation, Hygiene, and Health (WSH) department reports that 220 million people suffer from waterborne diseases annually. This emphasizes the importance of consuming water with ideal TDS levels for better health.
