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The CTD saves all measurements in the integrated 4MB non-volatile ring buffer (approx. 500,000 values).

Although especially designed for groundwater applications, the OTT CTD is also well suited for surface measurements

In addition to the proven product characteristics of high-quality pressure probes from OTT, the OTT CTD provides a conductivity measuring cell that meets all the demands of hydrological data collection.

Overall, the OTT CTD has proved to be reliable and rugged. This is ensured by the robust and reliable measuring cells, the high-quality stainless-steel housing, the kevlar-strengthened probe cable with integrated compensating capillary and an ingenious design.

An infrared interface allows the data to be conveniently read out or transferred from the device with a notebook. A well structured, self-explanatory operating program with all the necessary functions for data output and export, configuration and calibration is supplied.

And if remote data transmission is needed, with the OTT ITC the CTD can easily be equipped for data transmission using GMS/SMS or GPRS.

  • 4-electrode conductivity measuring cell minimizes polariation effects Robust, ceramic capacitive pressure cell with long-term stability Vented cable – barometric pressure changes are automatically compensated Corrosion and saltwater resistant housing material Electronic compartment sealed with potting resin – absolute watertight / no condensation inside Well structured, self-explanatory operating program with all the necessary functions: Configuration/ Calibration / Read-out / Data view & export Factory calibrated - ready for use Large 4 MB non-volatile ring memory (500.000 data) Easy and simple installation in observing wells 1” and bigger with adapter plates Battery exchange at site – easy to do without tools and without removing the instrument out of the well Ready for GSM/GRPS Com - Easy upgrade with data communication unit OTT ITC without any wiring work

  • Conductivity measurements can be used to characterize water quality changes relative to a baseline or to estimate the concentration of contaminants. The OTT CTD provides accurate and reliable data even in harsh environmental conditions. Although especially designed for groundwater applications, the OTT CTD is also well suited for surface measurements. Monitoring in areas of potential pollution, e.g.: EWnvironmental monitoring of groundwater and surface waters Monitoring of bank filtration wells Monitoring of saltwater intrusion Determination of geogenic groundwater salinization Renaturation of former sand and gravel pits or of wetlands Recultivation of contaminated sites and devastated open-cast mining areas Aquifer storage and recovering Areas used intensively for agriculture Tracer studies Estuary studies

Conductivity measurement Measurement range selectable
Measurement range 1: 0.001 … 2.000 mS/cm
Resolution: 0.001 mS/cm
Accuracy: ±0,5% of measurement value; (min ±0.001 mS/cm)
Units: mS/cm / µS/cm
Measurement range 2: 0.1 …100 mS/cm
Resolution: 0.01 mS/cm
Accuracy: ±1.5% of measurement value; (min ±0.01mS/cm)
Units: mS/cm
Waterlevel measurement  
Measurement range:
0...4 m, 0...10 m, 0...20 m, 0...40 m, 0…100 m
Resolution: 0.001 m / 0.1 cm / 0.01 ft / 0.1 inch
/ 0.0001 bar / 0.001 psi
Accuracy: ± 0.05 % FS
Units: m, cm, ft, inch, bar, psi
Temperature compensated operating range –5 °C +45 °C (icefree)
Temperature measurement  
Measurement range: –25 °C +70 °C
Resolution: 0.01 °C
Accuracy: ± 0.1 °C
Power supply Lithium oder Alkaline batteries
3 x 1.5 V battery (LR6·AA, FR6·AA)
Lifetime (@ 1 h interval)  
with Lithium-batteries > 5 years
with Alkaline-batteries > 1,5 years
Interface Infrared (IrDA)
Storage temperature –40 °C +85 °C
Memory 4 MB
Amount of values ca. 500 000
Measurement interval 5 sec ... 24 h
Storage interval 5 sec ... 24 h
with top cap adapter plates at 1', 2', 3', 4', 5', 6' wells/pipes
with universal mounting bracket ≥ 2' wells/pipes
Com unit L x Ø 400 mm x 22 mm
Sonde L x Ø 317 mm x 22 mm
Max cable length
1 ... 200 m ± 0,25 m
Housing Material ABS, V4A (DIN 1.4539)
Com unit (incl. bat) ca. 0.410 kg
Sonde ca. 0.430 kg
Protection class  
Com unit IP 67 (water column max. 2 m, duration max. 24 h)
Sonde IP 68

Related Categories
Water Quality Multiprobes
Aqualab Systems
Handheld Communications