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HACH COMPANY was established in 1947, in Ames, Iowa, USA. For more than 60 years, Hach has been the world market leader for Analytical Instrumentation for Complete Water Analysis, providing solutions for lab, process and field.

In 2002, GLI, a leading US manufacturer of process electro-chemistry analytical instruments, became part of the Hach Company family.

Water analysis has to be right. Our customers deserve complete, reliable solutions that they can be fully  confident in. Hach is your answer. We make water analysis simpler

Dissolved Oxygen Sensor (Luminescent)

LDO ™ Probe

Dissolved Oxygen Sensor (Luminescent)


Hach’s next generation LDO® (Luminescent Dissolved Oxygen) Probe requires no calibration for the entire 2 year life of the sensor cap, which means it is ready to start measuring your DO (Dissolved Oxygen) right out of the box. With an added cutting-edge 3D calibration procedure that is conducted prior to shipping, the probe will not drift and is more accurate than ever before.

By utilizing Hach’s breakthrough luminescent technology for measuring DO, this optical probe has no membranes which need to be replaced or electrolyte solution to replenish, making it virtually maintenance free. To make sure routine cleaning cycles are never missed, the probe offers operators customizable diagnostic alert indicators, ensuring the probe can operate at its maximum performance level. An improved body design optimizes the probe’s temperature sensor to provide an even faster response time to process variability as well. The probe comes with a three year warranty, and the sensor cap has a two year warranty.

So for supremely accurate DO measurements by a probe that does not require calibration and is membrane free, turn to an innovator in DO technology, and Hach’s next generation LDO Optical Dissolved Oxygen Probe.

  • No Calibration Required
  • No Membranes to Replace
  • No Missed Cleaning Cycles
  • No Drift
  • No Complications


Accuracy:± 0.05 ppm below 1 ppm
Accuracy 2:± 0.1 ppm below 5 ppm
Accuracy 3:± 0.2 ppm above 5 ppm
Accuracy 4:Temperature: ± 0.2 °C (± 0.4 °F)
Cable Length:10 m (33 ft)
Calibration Method:All Probes are factory calibrated and ready to use
Air Calibration: one point, 100% water saturated air
Sample Calibration: comparison to standard instrument, or comparison to Winkler Titration method
Dimensions (D x L):1.9 in x 10 in (48.25 mm x 254 mm)
Flow Rate:None required
Hazardous Location Ratings:ETL listed (cETLus marked) to Canadian and US General Safety and Hazardous (Class l, Div. 2) Locations
Interferences:No Interferences from the following: H2S, pH, K+, Na+, Mg2+, Ca2+, NH4+, Al3+, Pb2+, Cd2+, Zn2+, Cr (total), Fe2+, Fe3+, Mn2+, Cu2+, Ni2+, Co2+, CN-, NO3-, SO42-, S2-, PO43-, Cl-, anion active surfactants, crude oils, Cl2 < 4 ppm
Length:10 in ( 254 mm )
Measurement Range 2:0 to 20.00 mg/L (or ppm)
Measurement Range 3:0 to 200 % air saturation
Operating Temperature Range:0 to 50 °C (32 - 122 °F)
Pressure Range:max. 3.5 bar (50 psi)
Range:0 to 20.00 ppm
Repeatability:± 0.1 (mg/L) ppm
0.01 ppm DO
0.01 ppm DO 
0.1% saturation
Response Time:T95 < 60 s
Response Time - 20 °C:T90 < 40 s
Sensor Immersion Depth:Down to 345 kPa 345 kPa (50 psi), maximum; accuracy may not be maintained at this depth
Sensor Thread:1" NPT outer thread
Storage Conditions:-20 °C to 70 °C
Transmission Distance:1000 m (3280 ft.) maximum when used with a termination box
100 m (328 ft.) maximum
Weight:2.2 lbs. (1 kg) , probe only
Wetted Materials:Sensor Cap: Acrylic; Probe Body: CPVC, Polyurethane, Viton, Noryl, 316 Stainless Steel


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