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OVERVIEW
The HOBO MX801 Conductivity, Temperature and Depth (CTD) Data Logger measures conductivity, salinity and depth in fresh or saltwater. From its readings it calculates specific conductance, salinity and total dissolved solids (TDS).
The logger records absolute pressure, and HOBOconnect software converts it to water level. You can add dissolved oxygen monitoring with a 2-sensor adapter. For barometric compensation, use a HOBO MX20L Water Level logger as a reference.
Data is offloaded over Bluetooth using the HOBOconnect app on a compatible mobile device or Windows computer.
Key features
- 4-electrode conductivity sensor with a wide measurement range for freshwater or saltwater
- Centrally located conductivity sensor to minimise the effects of stilling wells and protective guards
- Durable ceramic water level sensor in the sensor tip for accurate shallow water level readings
- 1″ diameter for narrow wells
- Temperature sensor near the tip for fast response
- Specially treated stainless steel that holds up in saltwater
Depth range options
- MX801-CTD-04: 4 m
- MX801-CTD-01: 9 m
- MX801-CTD-02: 30 m
- MX801-CTD-03: 76 m
Need to track additional parameters, like Dissolved Oxygen or Depth?
No problem— Learn more about MX800 Multiparameter Data Loggers and configure a customised version HERE >> -
WHATS INCLUDED
Everything you need to start monitoring
MX801 Multiparameter Data Logger
Fully submersible Bluetooth-enabled logger designed for fast setup, guided calibration, and wireless data offload. Supports up to two interchangeable MX800 sensors for flexible water monitoring.
Learn More >>
W-CDT Conductivity & Temperature Sensor
Versatile, durable sensor measuring conductivity, temperature, and water level, enabling specific conductance, salinity, and TDS calculations. Features a 4-electrode design and rapid-response temperature element for accurate results in fresh or saltwater.
Learn More >>
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SPECIFICATIONS
MX801
Operating Range -40° to 50°C (-40° to 122°F), cannot be frozen in ice Radio Power 1 mW (0 dBm) Transmission Range Approximately 30.5 m (100 ft) line-of-sight Wireless Data Standard Bluetooth 5 Number of sensors that can be connected 2 Maximum Cable Length 120m (400 ft) Logging Rate 5 second to 18 hours Logging Modes Fixed interval (normal or statistics), burst, or multiple intervals with up to 8 user-defined logging intervals and durations, with pause and repeat options Start Modes Immediate, next interval or date & time Stop Modes Memory full, never stop (overwrite oldest data), date & time, or after a set logging period Water Detect Events are logged when logger is submerged or removed from the water (MX801 only) Time Accuracy ±1 minute per month 0° to 50°C (32° to 122°F) Battery Four AA, 1.5 V lithium batteries, user replaceable Battery Life With W-CTD or W-CT sensors: 2 years, typical with 1-minute logging interval or slower
With W-DO sensor: 1-year, typical with 5-minute logging interval or slower
With 2 CTD or CT sensors: 1 year (typical) with 1 minute logging interval
With both a DO sensor and a CTD/CT sensor: 1.5 years (typical) with 5 minute logging interval
With 2 DO Sensors: 1 year (typical) with 5 minute logging interval
Note: The following affect battery life:- Faster logging or statistics sampling intervals
- Burst logging mode
- Excessive readouts
- Remaining connected with the app
Memory 730,000 measurements, divided between channels (4 Mbyte memory) Data Download Time (with Blouetooth 5+ devices) Full memory: Approximately 3.5 minutes
120,000 measurements: 1 minute
May take longer the farther the device is from the loggerDimensions Logger diameter: 4.14 cm (1.63 inches)
Length without sensor: 20 cm (8 inches)
Length with W-CTD sensor: 36 cm (14 inches)
Length with W-CT sensor: 33 cm (13 inches)
Mounting loop: 12.7 x 22.6 mm (0.5 x 0.89 inches)Weight MX801: Logger only including batteries, 213g (7.51 oz)
Tapered collar for MX801 and MX802: 11g (0.39 oz)
2m Cable: 153g (5.40 oz)
Straight collar: 4g (0.14 oz)Wetted Materials Logger: PVC housing with polyester film label, PET sensor connector end cap and mounting handle with EPDM and Buna-N O-rings, passivated 316 stainless steel hardware rated for use in saltwater; MX802 also has ePTFE ventCollar: HDPE, titanium screwsNote: logger should be mounted so that no metal parts of the logger are in contact with other metalsEnvironmental Rating MX801: IP68; waterproof to 100m (with sensor(s) attached)* 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.
***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.
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/LCalibrated 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 greaterResolution 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
TDS: 0.1 mg/L
Salinity: 0.01 PSUResponse 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) waterRaw 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) waterRaw Pressure Accuracy** ±0.3% FS, 1.20 kPa (0.17 psi) maximum error Resolution <0.04 kPa (0.006 psi), 0.41 cm (0.013 ft) water 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) waterRaw 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 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) waterRaw 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 Temperature Measurements (All Models)
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 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
Depth sensor: ceramic
Conductivity sensor: PET, platinum plating on electrodes
Note: Sensor should be mounted so that it is not in contact with other metalsEnvironmental Rating IP68; Waterproof to pressure sensor burst pressure rating * 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.
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HOBOCONNECT SOFTWARE
Download the free HOBOconnect app for your iOS or Android mobile device or Windows computer today.
Onset’s HOBOconnect app, accessed from a free download from the iTunes or Google Play app store, or your pc, makes it quick and easy to configure compatible MX Series data loggers (chart below) and manage the collected data. From your mobile device, tablet, or Windows computer, users can view data in graphs, check the operational status of loggers, share data files and graph images for analysis in Excel, Numbers, and other applications, and store data in the cloud. HOBOconnect also makes it fast and easy to set up audible alarm notifications so users are immediately notified of problems.
Learn more about HOBOconnect >>
HOBO MX801 Conductivity, Temperature & Depth Data Logger Kit
Measure conductivity, salinity, temperature and water level in fresh or saltwater with one kit. The HOBO MX801 CTD fits 1″ wells, transfers data over Bluetooth, and is built to stay deployed in harsh conditions.
To order: Select one sensor depth below to complete your kit.
