WQ401 Dissolved Oxygen Sensor

Price$1,348.00 (US Only)



In Stock 0 - Available for Backorder

The dissolved oxygen sensor output is 4-20 mA with a three wire configuration. The dissolved oxygen sensor's electronics are completely encapsulated in marine grade epoxy within a stainless steel housing (online version has 1x8 inch PVC pipe nipple, threaded both ends with cap). The dissolved oxygen sensor uses a removable shield and dissolved oxygen element for easy maintenance.

  • Overview


    • Fully encapsulated electronics
    • 4-20 mA output
    • Marine grade cable with strain relief
    • Stainless steel housing
    • Replaceable DO element

    Global Water's PC320 Dissolved Oxygen Controller to use the dissolved oxygen sensor's output to control pumps or alarms. In addition Global Water offers GL500 dissolved oxygen data logger adds recording capabilities to the dissolved oxygen sensor. The GL500 dissolved oxygen data logger connects to the dissolved oxygen sensor's 4-20mA output to record data.

    Why Measure DO?

    Dissolved oxygen (DO) is the amount of oxygen (O2) dissolved in water. Dissolved oxygen measurements provide one of the best indicators of the health of a water ecosystem, as oxygen is a necessary element for all forms of life, including aquatic life. Oxygen enters water at the water surface through direct exchanges with the atmosphere. It is also produced as a byproduct of plant and phytoplankton photosynthesis. A decrease in dissolved oxygen levels is typically associated with an organic pollutant.

    Dissolved oxygen is used by plants and animals for respiration, and by aerobic bacteria in the process of decomposition. When organic matter (such as animal waste or improperly treated wastewater) enters a body of water, algae growth increases. As the plant material dies off and decomposes, dissolved oxygen levels decrease. If the water at the surface is not mixed with deeper water layers, the water's dissolved oxygen levels can become stratified. Dissolved oxygen levels can also vary according to the time of day, weather, and temperature.

    Dissolved oxygen in water can range from 0-18 parts per million (ppm), but most natural water systems require 5-6 ppm to support a diverse population. As dissolved oxygen levels drop below 5.0 mg/L, aquatic life is put under stress. As dissolved oxygen levels decrease, pollution-intolerant organisms are replaced by pollution-tolerant worms and fly larvae. If dissolved oxygen levels fall below 1-2 mg/L for a few hours, large fish kills can result.

  • Specifications
    WQ401 DO Sensor  
    Output 4-20 mA

     0-100% Saturation, 0-8 ppm, temperature compensated to 77°F (25°C)

    Accuracy ±0.5% of full scale
    Maximum Pressure

    40 psi

    Operating Voltage 10-36 VDC

    Current Draw

    15.5 mA plus sensor output

    Warm Up Time

    10 seconds minimum

    Operating Temperature -40 to +131°F (-40 to +55°C)

    0.001 FEP Teflon (standard)

    Combined Error -2% FS
    Size of Probe Standard: 11" L x 1-1/4" Diameter (27.9 cm L x 3.2 cm Dia.)
    Online: 12" L x 2" Diameter (30.5 cm L x 5 cm Dia.) (end cap)
    Weight Standard and Online 1 lb. (454 kg)
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