TDS concept is an imported, in the United States, Taiwan, widely used in the field of water treatment, the TDS value of the measurement tool is generally used TDS pen, the principle of its measurement is in fact through the measurement of the conductivity of the water and thus indirectly reflecting the TDS value. In the physical sense, the more dissolved substances in the water, the greater the TDS value of the water, the better the conductivity of the water, the greater the value of its conductivity.
In layman's terms: the TDS value represents the content of impurities in the water dissolved in the water, the larger the TDS value, the greater the content of impurities in the water, and vice versa, the content of impurities is small.
Factors affecting the TDS value test:
Water temperature: TDS pen can not be used to measure the high temperature of the body of water (eg: hot water)
Water flow rate: TDS pen can not be used to measure the larger body of water shaking
Water contamination: TDS pen can not be used to measure the pollution of the body of water with high concentration
Chinese means dissolved in the water. Total solids content, TDS meter is designed for this meter, can see the ppm value of inorganic or organic matter in the water. However, this is only an initial test and does not provide accurate information on what is in the water. If you need the correct composition of the inclusions, you should still send it for testing. Detection of total dissolved solids in water (TDS) that is, to test the total amount of various types of organic or inorganic substances dissolved in water, using the unit of ppm or milligrams per liter (mg/l). Its conductive instrumentation measures conductive substances in water such as suspended matter, heavy metals and conductive ions. How to use it? (i) The temperature of the water during measurement should be maintained at about 25 degrees Celsius. Remember, too high a temperature will increase the TDS value and affect the correctness. (B) the LCD screen shows the value of the TDS value, if the TDS meter shows 100 degrees of digital, that represents the content of substances dissolved in the water positive ions or negative ions for the total number of 100 ppm (tolerance ± 5 ppm), the higher the number, said the more substances in the water. (C) Beijing area tap water in the average of 250ppm or so, RO water can be reduced to less than 30ppm, when the value of more than 30ppm, it must be considered to replace the RO filter membrane or ask a technician inspection and repair. Of course, the TDS meter is not everything, it also has its blind spots and shortcomings: (a) TDS can only measure the conductive substances in the water, but can not measure bacteria, viruses and other substances. (B) rely solely on TDS water quality test to determine whether the water can be raw drinking, and is not the most correct approach; by high temperature can not be extinct bacteria or viruses, must be measured through a more sophisticated instrument.
TDS unit:
(1) milligrams (mg)/liter shows how many milligrams of total dissolved solids in 1 liter of water.
(2) PPM solution parts per million concentration unit. Refers to the number of milliliters of solute contained in one million milliliters of solution or indicates the number of grams of solute contained in one million grams of solution.
(3) conversion relationship: 1mg / l = 1PPM
National standard GB5749-2006 "drinking water health standards" in the drinking water of the total dissolved solids (TDS) have limited requirements: total dissolved solids ≤ 1000mg / L