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Pocket and handheld TDS Meters measure the level of total dissolved solids (TDS) in your water and monitor the performance of a reverse osmosis (RO) membrane.
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Handheld meters are ideal for all consumer and commercial water purification applications, including waste water regulation, aquaculture, hydroponics, and more. Total Dissolved Solids (TDS) are the total amount of mobile charged ions, including minerals, salts, or metals, dissolved in a given volume of water expressed in units of mg per unit volume (mg/L) or parts per million (ppm).
How Does a TDS Meter Work?
A TDS meter or tester monitors the amount of current passing between the two electrodes to find how many ions are in solution and allows you to calculate the TDS reading. Applying a voltage between two or more electrodes causes the negatively charged ions to move towards the positive ones, while the positively charged ions move towards the negative ones.
Tips for Using a TDS Meter
Rinse the end of the TDS meter that will be submerged in water with fresh water. Build-up of salts on the meter will interfere with proper operation and skew the readings.
Be careful not to touch the TDS electrode surfaces with your hands or an abrasive cloth. To clean the TDS electrodes, soak the tips in vinegar or diluted hydrochloric acid (muriatic acid) and rinse them well with water. Check your TDS meter handbook for individual cleaning methods.
If you are using a TDS meter to monitor the performance of an RO membrane, then the TDS measurement should decrease from the original number by at least a factor of 10. For example, if your tap water is 231 ppm, then the water from your RO system should be less than 23 ppm. A decrease less than a factor of 10 usually indicates a problem with the RO membrane.