Water Survey Tech

Product Detail

Nitrate probe SPS-NO3

  • Robust and virtually maintenance-free single-parameter sensor (SPS) for measuring nitrate ( NO3– , NO3-N)
  • Slim design (Ø 48.3 mm) for observation wells with minimum 3“diameter
  • High measuring accuracy, drift-free
  • Available in different measuring ranges up to max. 0-266 mg/L NO3
  • Made of 1.4571 stainless steel
  • Output: RS485 (SHWP, Modbus RTU) to connect with SEBA data loggers

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High accuracy, drift-free: Using a photodiode to take differentiated measurements of the incoming light at wavelengths of 212 nm, 254 nm, and 360 nm, the SPS-NO3 is able to determine the nitrate concentration with high precision and long-term stability. Organic compounds and turbidity are automatically compensated and therefore have little or no influence on the accuracy.


Optimized measuring ranges: Depending on the expected nitrate loads, the SPS-NO3 can be optimized for the use in groundwater and surface water by choosing the suitable path length. 4 path lengths with different measuring ranges of maximum 0-266 mg/L NO3– are available as standard.


Robust and slim design: The SPS-NO3 consists of a high-quality stainless steel housing (1.4571) and is ideally suitable for rough field use in groundwater and surface water. The nano-coating of the measuring window effectively prevents algae growth. The slim design allows installation in 3” observation wells.


Almost maintenance-free: In comparison to ion-selective nitrate electrodes, the calibration of the SPS-NO3 needs to be checked sporadically, saving time and money during ongoing measurement operations. An optionally available cleaning module with wiper additionally ensures that the measuring windows are free from unwanted fouling.


Modular and self-sufficient: Configure your field monitoring station from a wide range of SEBA data loggers (Unilog-Light, Unilog, UnilogCom, NetLogCom) in combination with other water quality probes (MPS-PTEC, MPS-D3, MPS-D8, MPS-K16) with or without remote data transmission, battery or solar-powered.

  • Long-term monitoring in surface water and groundwater
  • Drinking water and discharge monitoring

Mobile configuration module

Data logger:



Cleaning module with wiper

Nitrate probe:

Lightsource  Xenon-flashlight

Detector  4 photo diodes + filter

Measurement principle:


Optical path:

1 mm, 2 mm, 5 mm


NO3-, NO3-N

Measurement range:

path length: 1 mm:  0…266 mg/L NO3– ;

path length: 2 mm:  0…133 mg/L NO3– ;

path length: 5 mm:  0…53 mg/L NO3– ;

further measurement ranges/path lengths on request

Measurement accuracy:

path length: 1 mm: ±5 % + 4,4 mg/L NO3– ;

path length: 2 mm: ±5 % + 2,2 mg/L NO3– ;

path length: 5 mm: ±5 % + 0,88 mg/L NO3– ;

Turbidity compensation:


Internal data logger:

appr. 2 GB

Reaction Time T100:


Measurement interval:

≥ 30 s

Maximum pressure:

0-3 bar


Stainless steel (1. 4571/1.4404) or Titanium 3.7035


approx. 470 x 48 mm (10 mm pathway)


VA ca. 3 kg


TI ca. 2 kg


Digital Ethernet (TCP/IP), RS-485 (Modbus RTU)

Power consumption:

less or equal to  8 W

Power supply:

12…24 VDC (± 10 %)

Calibration /maintenance interval:

24 month

Maximum pressure:

With cable 0 – 3 bar

Operating temperature:

+2…+40 °C

Protection class:



Cleaning module with Anti Fouling Wiper

Wiper blades for cleaning module