What is Total Dissolved Solids

Total dissolved solids refers to the total concentration of substances – including inorganic salts and organic matter – dissolved in a given volume of water, which is expressed in units of mg per litre or parts per million.

Common inorganic salts that are found in water are cations like calcium, magnesium, potassium, and sodium, as well as anions like carbonates, nitrates, bicarbonates, chlorides and sulphates. Cations are positively charged ions, whereas anions are negatively charged ions.

Aquaread Total Dissolved Solids Sensor

If you’re looking to discover an easy way to test for total dissolved solids, our TDS meter is an efficient and reliable solution.

Aquaread’s TDS measurement is calculated within our software using the electrical conductivity (EC) measurement and temperature in a simple equation.

The output for the TDS sensor is in parts per million (PPM) or mg/L.

A TDS value gives a measurement of the amount of organic and inorganic substances dissolved within the water.


Key Features

  • Calculated parameter that’s always included on every Aquaprobe and Aquasonde.
  • Also included in the AquaPlus optical dissolved oxygen sensor.
  • Uses the corrosion-resistant gold-coated stainless steel EC sensor.
  • Measurement range 0 – 100,000 mg/L.
  • Resolution 2 auto ranging scales: 0 – 9999mg/L, 10.00 – 100.00 mg/L.
  • Accuracy of 1% of reading.
  • Requires no calibration – this is taken care of when you calibrate the EC sensor

Our total dissolved solids sensors come as standard on many of our probes — below are some examples. To see all of the probes that feature TDS sensor, please visit the Products section.



Portable, GPS AquaPlus Optical DO/EC system



Advanced portable multi-parameter Aquaprobe.



The Aquasonde-5000 has 4 spare ports. They can house any combination of ISE and Optical sensors.

Always included

The TDS sensor is included on every Aquaprobe and Aquasonde, it is also included in the AquaPlus optical dissolved oxygen sensor.