Salinity Sensor (SAL-BTA)

Specifications and User Guide

Troubleshooting

  • Primary Test: Plug in the sensor and start up the data-collection program. Place the sensor in distilled water. The reading should be at or near 0 ppt. Place the sensor in a 35 ppt salinity standard solution. The reading should be at or near 35 ppt. Note: This standard solution can be purchased from Vernier or made by adding 33.03 g reagent grade NaCl to enough distilled or deionized water to make 1.00 liter of solution.
  • Secondary Test: Plug in the sensor and start up the data-collection program. Place the sensor in distilled water and then move the sensor to a container of tap water. The readings should change from 0 ppt to a salinity value that is appropriate for your region of the country.

Additional Troubleshooting

Specifications

  • Range of Salinity Sensor: 0 to 50 ppt (0 to 50,000 ppm)
  • Accuracy
    ⚬ using factory calibration: ±3% of full-scale reading
    ⚬ using custom calibration: ±1% of full-scale reading
  • Response time: 90% of full-scale reading in 10 s.
  • Temperature compensation: automatic from 5 to 35 °C
  • Temperature range (can be placed in): 0 to 80 °C
  • Cell constant: 10 cm-1
  • Description: dip type, epoxy body, parallel platinum electrodes
  • Dimensions: 12 mm OD and 150 mm length
  • Typical calibration coefficients: slope 16.3 ppt/V; intercept 0 ppt

Calibration

Calibrate? For many experiments, calibrating the Salinity Sensor is not required. We store a calibration equation on each sensor before shipping it, which is used as a default by our software.

For the most accurate measurements with this sensor, we recommend calibration. It is a simple process that takes only a few minutes. For instructions for Salinity Sensor calibration, see How do I calibrate my sensor?

CALIBRATION SOLUTION

If you choose to calibrate the Salinity Sensor, you will want an accurate standard solution. Vernier sells a 35 ppt Salinity Standard (SAL-ST). If you prefer to prepare your own 35 ppt standard solution using solid NaCl, use a container with accurate volume markings (e.g., volumetric flask). Add 33.03 g reagent grade NaCl to enough distilled water to make one liter of solution.

Note: The Practical Salinity Scale 1978 was developed relative to a KCl solution. Standard Methods for the Examination of Water and Wastewater states that “A seawater with a conductivity at 15°C equal to that of a KCl solution containing a mass of 32.4356 g in a mass of 1 kg of solution is defined as having a practical salinity of 35.”

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Published: August 22, 2019. Updated: April 30, 2025.