Onset HOBO CTD Sensors
Features
- 4-electrode conductivity sensor provides wide measurement range for monitoring freshwater or saltwater
- Durable ceramic water level sensor, located in the sensor tip for accurate measurement of shallow water levels
- Get water level directly with the MX802, no need for post-processing
- Free ground shipping
- Expedited repair and warranty service
- Lifetime technical support
- More
The CTD sensor is an interchangeable sensor that works with HOBO MX800 Series Water Loggers to measure conductivity, temperature, and water level. With this sensor attached to a HOBO MX800 Series Water Logger, the logger can also calculate specific conductance, salinity, and total dissolved solids (TDS).
The CTD sensor can be attached directly to the fully submersible MX801 model, or attached via cable to the direct read MX802 model, which doesn’t require having to pull the sensor out of the water to download data.
| Sensor | |
| Dimensions | 2.5 cm (1 inch) diameter, 15 cm (6 inches) length |
| Weight | Approximately xx g (xx oz) in air; approximately xx g (xx oz) in saltwater |
| Wetted Materials | Passivated 316 Stainless steel housing rated for use in saltwater, Viton and Buna-N O-rings, PET sensor connector |
| Conductivity sensor: PET, platinum plating on electrodes | |
| Note: Sensor should be mounted so that it is not in contact with other metals | |
| Environmental Rating | IP68; Waterproof to 100m |
| Conductivity Measurements | |
| Measurement Range | Electrical conductivity and specific conductance: 0 to 100,000 µS/cm |
| Salinity using PSS-78: 2 to 42 PSU | |
| Total Dissolved Solids (TDS): 0 to 100,000 mg/L | |
| Calibration Range | Electrical conductivity: 50 to 80,000 µS/cm |
| 5° to 35°C (41° to 95°F) | |
| Accuracy | Conductivity: +/-2% or 15 µS/cm whichever is greater |
| Salinity: +/-2% of reading or 0.1 PSU, whichever is greater | |
| Resolution | Conductivity:0.1 µS/cm from 0 to 1,000 µS/cm | 1 µS/cm from 1,000 to 10,000 µS/cm |10 µS/cm from 10,000 to 100,000 µS/cm |
| Salinity: 0.01 PSU | |
| TDS: 0.1 mg/L | |
| Response Time | 1 second to 90% at a stable temperature |
| Temperature Measurements | |
| Range | -20° to 50°C (-40° to 122°F), non-freezing water |
| Accuracy | ±0.15°C (±0.27°F) from 0° to 50°C (32° to 122°F) |
| Resolution | 0.01°C at 25°C (0.018°F at 77°F) |
| Response Time | 3 minutes to 90% in water (typical) |
| Drift | <0.1°C (0.18°F) per year |
| Absolute Pressure and Water Level Measurements W-CTD-04 | |
| Range | 0 to 145 kPa (0 to 21 psia); approximately 0 to 4 m (0 to 13 ft) of water depth at sea level, or 0 to 7 m (0 to 23 ft) of water at 3,000 m (10,000 ft) of altitude |
| Factory Calibrated Range | 69 to 145 kPa (10 to 21 psia), 0° to 40°C (32° to 104°F) |
| Burst Pressure | 310 kPa (45 psia) or 18 m (60 ft) depth |
| Water Level Accuracy* | Typical error: ±0.075% FS, 0.3 cm (0.01 ft) water |
| Maximum error: : ±0.15% FS, 0.6 cm (0.02 ft) water | |
| Raw Pressure Accuracy** | ±0.3% FS, 0.43 kPa (0.063 psi) maximum error |
| Resolution | <0.014 kPa (0.002 psi), 0.14 cm (0.005 ft) water |
| Pressure Response Time*** | <1 second to 90% at a stable temperature |
| Absolute Pressure and Water Level Measurements W-CTD-01 | |
| Range | 0 to 207 kPa (0 to 30 psia); approximately 0 to 9 m (0 to 30 ft) of water depth at sea level, or 0 to 12 m (0 to 40 ft) of water at 3,000 m (10,000 ft) of altitude |
| Factory Calibrated Range | 69 to 207 kPa (10 to 30 psia), 0° to 40°C (32° to 104°F) |
| Burst Pressure | 310 kPa (45 psia) or 18 m (60 ft) depth |
| Water Level Accuracy* | Typical error: ±0.05% FS, 0.5 cm (0.015 ft) water |
| Maximum error: ±0.1% FS, 1.0 cm (0.03 ft) water | |
| Raw Pressure Accuracy** | ±0.3% FS, 0.62 kPa (0.09 psi) maximum error |
| Resolution | <0.02 kPa (0.003 psi), 0.21 cm (0.007 ft) water |
| Pressure Response Time*** | <1 second to 90% at a stable temperature |
| Absolute Pressure and Water Level Measurements W-CTD-02 | |
| Range | 0 to 400 kPa (0 to 58 psia); approximately 0 to 30.6 m (0 to 100 ft) of water depth at sea level, or 0 to 33.6 m (0 to 111 ft) of water at 3,000 m (10,000 ft) of altitude |
| Factory Calibrated Range | 69 to 400 kPa (10 to 58 psia), 0° to 40°C (32° to 104°F) |
| Burst Pressure | 500 kPa (72.5 psia) or 40.8 m (134 ft) depth |
| Water Level Accuracy* | Typical error: ±0.05% FS, 1.5 cm (0.05 ft) water |
| Maximum error: ±0.1% FS, 3.0 cm (0.1 ft) water | |
| Raw Pressure Accuracy** | ±0.3% FS, 1.20 kPa (0.17 psi) maximum error |
| Resolution | ±0.3% FS, 1.20 kPa (0.17 psi) maximum error |
| Pressure Response Time*** | <1 second to 90% at a stable temperature |
| Absolute Pressure and Water Level Measurements W-CTD-03 | |
| Range | 0 to 850 kPa (0 to 123.3 psia); approximately 0 to 76.5 m (0 to 251 ft) of water depth at sea level, or 0 to 79.5 m (0 to 262 ft) of water at 3,000 m (10,000 ft) of altitude |
| Factory Calibrated Range | 69 to 850 kPa (10 to 123.3 psia), 0° to 40°C (32° to 104°F) |
| Burst Pressure | 1,200 kPa (174 psia) or 112 m (368 ft) depth |
| Water Level Accuracy* | Typical error: ±0.05% FS, 3.8 cm (0.125 ft) water |
| Maximum error: ±0.1% FS, 7.6 cm (0.25 ft) water | |
| Raw Pressure Accuracy** | ±0.3% FS, 2.55 kPa (0.37 psi) maximum error |
| Resolution | <0.085 kPa (0.012 psi), 0.87 cm (0.028 ft) water |
| Pressure Response Time*** | <1 second to 90% at a stable temperature |
| *Water Level Accuracy: With accurate reference water level measurement, known water density, and a stable temperature environment. System Water Level Accuracy equals the sum of the Barometric Water Level Accuracy plus the selected CTD sensor Water Level Accuracy. | |
| ** Raw Pressure Accuracy: Absolute pressure sensor accuracy includes all sensor drift, temperature, and hysteresis-induced errors. | |
| ***Changes in Temperature: Allow 20 minutes in water to achieve full temperature compensation of the pressure sensor. There can be up to 0.5% of additional error due to rapid temperature changes. | |
Select Options
In The News
Climate Change and Microplastics: Monitoring Lake Champlain
Most people go to Lake Champlain for its exceptional views and thrilling boating, but it’s also home to a wide variety of interesting aquatic research projects. From studying microplastics to thermal dynamics of the lake, Timothy Mihuc, director of the Lake Champlain Research Institute (LCRI) at the State University of New York at Plattsburgh (SUNY Plattsburgh), has spent his career studying aquatic ecosystems. As an aquatic biologist, he’s the main investigator on Lake Champlain’s research studies while also managing their grants, employees, and their hands-on buoy work. Over the years, LCRI has received a number of environmental grants that aid in its monitoring research.
Read More
Current Monitoring after the Francis Scott Key Bridge Collapse
On March 26th, according to The Baltimore Sun , a 984-foot, 112,000-ton Dali lost propulsion and collided with a support column of the Francis Scott Key Bridge, collapsing the structure. Soon after the event, search and rescue, salvage crews, and other emergency responders were mobilized after the collision. As salvage efforts progressed in early April, NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) responded to a request for real-time tidal currents data and deployed a current monitoring buoy—CURBY (Currents Real-time BuoY)—into the Patapsco River north of the Francis Scott Key Bridge.
Read More
Soundscapes of the Solar Eclipse: Citizen Science Supporting National Research
On April 8, 2024, millions of people around the world had their eyes glued to the sky to witness a historic cosmic event. The total solar eclipse captured the headlines and the minds of many who became eager to gaze at the heavens as the sky went dark for a few minutes. However, not everyone used their sense of sight during the eclipse, some were listening to the sounds of the natural world around them as the light faded from above. The Eclipse Soundscape Project is a NASA-funded citizen science project that focuses on studying how the annular solar eclipse on October 14, 2023, and the April 8, 2024 total solar eclipse impacted life on Earth. The project revisits an initiative from the 1930s that showed animals and insects are affected by solar eclipses.
Read More
