• Measures total dissolved gas pressure
  • Most accurate and stable submersible
    dissolved gas sensor
  • Suitable for industrial applications
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The GTD-Pro™ is the most accurate and stable dissolved gas sensor on the market. It measures the sum of the partial pressures of all dissolved gases, i.e. gas tension.

In most natural waters N2 and O2 are the dominant dissolved gases. If oxygen is measured independently, pN2 can be determined from gas tension. The two gases together can be used to make substantially improved estimates of net biological production.

Total dissolved gas measurements have also been used to study air-sea gas exchange and other upper ocean physical, chemical and biological processes.

Also available is the HGTD-Pro™ hurricane model which is a smaller, lighter sensor that equilibrates faster that the GTD-Pro™.

How stable is the GTD-Pro™? One GTD-Pro™ was repeatedly deployed over a period of 6 years at depths up to 120 meters, first in the Labrador Sea, then in the Equatorial Pacific and North Pacific. Over that 6 year period, the GTD-Pro™ drifted from calibration by less than 0.001% per year. Not every GTD-Pro™ will be this stable, but all are guaranteed to drift no more than 0.02% per year.


  • High precision and accuracy
  • User friendly setup and operation
  • Low power
  • Unique antifouling protection

Physical Dimensions

  GTD-Pro™ HGTD-Pro™
Length: 35 cm 22.9 cm
Diameter: 10 cm 8.3 cm
Weight: 3 kg in air, 0 kg in water 1.6 kg in air, 0.6 kg in water
Housing: Delrin® (300 m depth) Delrin® (300 m depth)

All of our instruments are covered by a ONE-YEAR LIMITED WARRANTY

Download Data Sheet



Accuracy: < 0.02 mbar / yr drift

Resolution: 0.002 mbar

Equilibration time (t63): 3 min (GTD-Pro)
1 min (HGTD-Pro)

Measurement range:

  • Minimum 800 mbar
  • Maximum 2000 mbar
    (other maximum limits available)

Electrical Characteristics

Input voltage:

  • 10-30 VDC

Power consumption:

  • 0.4 W

Sample rate: 1 second (user selectable with datalogger / controller)