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Milwaukee C65 Low Range Waterproof Conductivity Pen with ATC and Replaceable Electrode

SKU: 9139-C65~ea

SKU: 9139-C65~ea

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Milwaukee C65 Low Range Waterproof Conductivity Pen with ATC and Replaceable Electrode

The Milwaukee C65 Conductivity Pen is designed for aquariums, aquaculture, agriculture and pools.  It helps to make sure that fish or plants are receiving the right amount of nutrients to keep the water clean and clear.


  • Measures conductivity and temperature with automatic temperature compensation
  • Ideal range for Aquaculture (0 to 1999 uS/cm)
  • Units directly in uS/cm (no conversions required)
  • Factory calibrated with the ability to recalibrate if needed
  • Replaceable electrode
  • Fully waterproof to IP65
  • 250 hours continuous use (3 x 1.5V batteries included)


  • Range: 0 to 1999 uS/cm
  • Resolution: 1 uS/cm
  • Accuracy: ±2% Full Scale
  • Typical EMC Deviation: ±2% Full Scale
  • Temperature Compensation: Automatic from 5 to 50°C (41 to 122°F), with ß=2%/°C
  • Calibration: Manual, at 1 point through trimmer
  • Probe: MA73075 (replaceable)
  • Environment: 0 to 50°C / 32 to 122°F; max RH 100%
  • Battery Type: 3 x 1.5V (included)
  • Battery Life: Approx. 250 hours of continuous use
  • Dimensions: 6.5 x 1.2 x 1.2 inches (165 x 30 x 30 mm)
  • Weight: 3.5 ounces (0.99 g)

Milwaukee C65 Manual



EC electrodes can develop nutrient build up over time. To minimize build up, always rinse the probe in fresh tap or DI water after every use.


The Milwaukee EC Pen, like all conductivity meters, provides a measure of electrically charged ions in a solution and is an absolute measure of conductivity.

EC is often converted to TDS in parts per million (ppm). Different scales include the 500 scale, 650 scale and the 700 scale. However, true PPM can only be determined through chemical analysis.

Your uS/cm reading can be approximately converted to TDS (ppm) as shown in the examples below.

1 uS/cm = 0.5 ppm on a .5 factor scale 
1 uS/cm = 0.7 ppm on a .70 factor scale (442)