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Milwaukee CD611 Digital Conductivity Pen (EC)

SKU: 9139-CD611~ea

SKU: 9139-CD611~ea

This product may be backordered. General ETA is 10-14 business days for delivery. Please feel free to contact us: or 1-800-535-3751 to confirm stock / lead time. We appreciate your business!

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Milwaukee CD611 Digital Conductivity Pen (EC)

The Milwaukee Conductivity Pen is designed for hydroponic and other growers to help ensure that plants are receiving the right amount of nutrients.


  • Measures conductivity and temperature with automatic temperature compensation
  • Ideal range for hydroponics (0 to 20,000 µS/cm)
  • Units in µS/cm easily convertible to ppm
  • Factory calibrated with the ability to recalibrate if needed
  • 350 hours continuous use (3 x 1.5V batteries included)


  • Range: 0 to 20000 µS/cm
  • Resolution: 100 µS/cm
  • Accuracy: ±2% Full Scale
  • Temperature Compensation: Automatic from 5 to 50°C, with ß=2%/°C
  • Calibration: Manual, at 1-point through trimmer
  • Environment: 0 to 50°C / 32 to 122°F; max RH 100%
  • Battery Type: 4 x 1.5V Alkaline (included)
  • Battery Life: Approx. 350 hours of continuous use
  • Dimensions: 6 x 1.2 x 0.95 inches
  • Weight: 3 ounces

 Milwaukee CD611 Manual



EC electrodes can develop nutrient buildup over time. To minimize buildup, always rinse the probe in fresh tap 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 mS/cm reading can be approximately converted to TDS (ppm) as shown in the examples below.

2,000 µS/cm = 2.0 mS/cm = 1000 ppm on .50 factor scale
2,000 µS/cm = 2.0 mS/cm = 1400 ppm on the 442 scale or .70 factor scale