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HM Digital TDS-4TM TDS Meter

he TDS-4 is an ideal pocket sized meter that can be used for any and all applications, typically for testing TDS and salt levels of freshwater aquariums and ponds. It can also be used for testing water filtration and purification systems, such as RO and DI, to know when to changes filters and membranes.

  • Hold Function saves measurements for convenient recording
  • Auto Off Function to conserve battery life (After 10 Minutes)
  • Built in digital thermometer
  • Pocket sized makes it ideal for portability and storage
  • Factory Calibrated with a 342 ppm NaCl solution


  • Hydroponics
  • Potable water
  • Aquariums and Reef tanks
  • Reverse Osmosis
  • Water Treatment
  • Horticulture