HOBO Salt Water Conductivity/Salinity Data Logger

Data Loggers

HOBO Salt Water Conductivity/Salinity Data Logger

  • Vendor:Onset
Availability: In Stock
Qty Price
Buy 1 $975.00 ea
Buy 10 $901.88 ea

HOBO data loggers requires HOBOware software (USB interface cable included w/CD purchase) and a communications device. HOBOware Pro is required when using the U-DTW-1 Waterproof shuttle. See compatible items below.


The HOBO U24-002-C is a cost-effective data logger for measuring salinity, conductivity and temperature in saltwater environments with relatively small changes in salinity (±5,000 μS/cm) such as saltwater bays, or to detect salinity events such as upwelling, rainstorm, and discharge events. It can also be used to gather salinity data for salinity compensation of HOBO U26 Dissolved Oxygen logger data.

Note: When monitoring salinity in waters with more than +/-5,000 uS/cm variation, refer to the accuracy shown in Plot C in the product specifications to determine if the accuracy is acceptable for your needs. Monthly field calibration readings are typically required to achieve the best accuracy.

Highlighted Features

  • Non-contact sensor provides long life
  • Provides easy access to sensor for cleaning and shedding air bubbles
  • Two user-selectable ranges provide measurements from 100 to 55,000 uS/cm.
  • The Delrin housing will not corrode in saltwater
  • HOBOware Pro software enables start/end-point calibration to compensate for any fouling and provides easy conversion to specific conductance and salinity using the Practical Salinity Scale 1978 (PSS-78)
  • USB optical interface provides high-speed, reliable salinity data offload in wet environments
  • Compatible with the HOBO Waterproof Shuttle for easy and reliable data retrieval and transport
The HOBO U24 Conductivity/Salinity data logger features a non-contact sensor with a Titanium Pentoxide coating. This coating prevents the sensor from coming in contact with the water, which in turn prevents tarnishing or corrosion associated with traditional electrode sensors. This sensor coating is also inert, enabling fouling to be easily wiped off the sensor.

In what environment does this data logger operate?

This data logger operates in outdoor and underwater environments.

What measurements does this data logger support?

The U24-002-C data logger supports the following measurements: Conductivity/Salinity and Temperature

Measurements: Actual Conductivity, Temperature, Specific Conductance at 25C (calculated), Salinity (calculated using PSS-78, the Practical Salinity Scale 1978)

Conductivity Measurement Range (Calibrated Range)
High range: 5000 to 55,000 uS/cm
Low range: 100 to 10,000 uS/cm
Over the range of 5 to 35C (41 to 95F)

Temperature Measurement Range: 5 to 35C (41 to 95F)

Plot A: Salinity Range (U24-002-C)*

Plot B: Specific Conductance Range in Saltwater

Plot C:
Specific Conductance High-Range Accuracy (U24-002-C)

Specific Conductance Accuracy (in Calibrated Range using Conductivity Assistant and Calibration Measurements)
Low range: 3% of reading or 50 µS/cm, whichever is greater
High range: 5% of reading, in waters within a range of
±3,000 µS/cm; waters with greater variation can have substantially greater error (see Plot C)

Conductivity: 2 uS/cm
Temperature: 0.01°C (typical 0.02°F)

Conductivity drift: Up to 12% sensor drift per month, exclusive of drift from fouling. Monthly start- and end-point calibration should be used with the HOBOware Conductivity Assistant to achieve the specified Specific Conductance accuracy.
Response time: 1 second to 90% of change (in water)
Operating range: -2 to 36C (28 to 97F) – non-freezing
Memory: 18,500 temperature and conductivity measurements when using one conductivity range; 14,400 sets of measurements when using both conductivity ranges (64kbytes)
Sample rate: 1 second to 18 hrs, fixed or multiple-rate sampling with up to 8 user-defined sampling intervals
Clock accuracy: +/- 1 minute per month
Battery life: 3 years (@ 1 min logging)
Maximum depth: 70 m (225')
Weight: 193 gm (6.82 ounces), buoyancy in freshwater: -59.8 gm (-2.11 ounces)
Size: 3.18 cm diameter x 16.5 cm, with 6.3 mm mounting hole (1.25" diameter x 6.5", ¼" hole)
Wetted housing materials: Delrin housing, epoxy, stainless steel retaining ring, polypropylene, Buna rubber O-ring, titanium pentoxide (inert coating over sensor) – all materials are suitable for long-term use in saltwater.

CE compliance: The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).