Milwaukee MW804 MAX Waterproof 4-in-1 pH / EC / TDS / Temp Tester

SKU: 9139-MW804~ea

Milwaukee MW804 MAX Waterproof 4-in-1 pH / EC / TDS / Temp Tester

SKU: 9139-MW804~ea
Regular price $242.42 CAD
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Milwaukee MW804 MAX Waterproof 4-in-1 pH / EC / TDS / Temp Tester with Replaceable Probe

The Milwaukee MW804 MAX Waterproof 4-in-1 Tester is designed as an all-in-one solution for growers.  It is accurate to ±0.05 pH, EC/TDS to 2% Full Scale and ±0.5°C / ±1°F for temperature.

A large dual level LCD screen makes reading results easy while a stability indicator and hold function freezes the display.  With automatic calibration and 5 memorized calibration points, the tester can be quickly and easily calibrated to a higher accuracy compared with manual calibration.  It is designed with a double junction probe which offers a longer life.  The tester is lightweight and fully waterproof to IP67. 


  • Fast, easy to read results with large digital dual LCD readout
  • Extreme accuracy to ±0.05 pH, EC / TDS 2% Full Scale and Temperature ±0.5 C / ±1 F
  • Range 0.00 – 14.00 pH, EC 20.00 mS/cm, TDS 0 - 10.00 ppt, Temperature: 0.0 to 50.0 C / 32.0 to 122.0 F
  • Lightweight and portable at just 3.5 ounces
  • Easy measurement: just place the probe in the sample, gently stir, wait for the stability indication to show a stable reading and then freeze the reading
  • Simple push button, automatic one or two-point calibration with 5 saved calibration points
  • Gel-filled, double junction pH electrode for low maintenance and high performance
  • Auto shut off and low power demand for approx. 100 hours of continuous use (batteries included)


  • pH Range: 0.00 to 14.00 pH
  • EC Range: 20.00 mS/cm
  • TDS Range: 0 to 10.00 ppt
  • Temp Range: 0.0 to 50.0°C / 32.0 to 122.0°F
  • pH Resolution: 0.01 pH
  • EC Resolution: 0.01 mS/cm
  • TDS Resolution: 0.01 ppt
  • Temp Resolution: 0.1 C / 0.1 F
  • pH Accuracy: ±0.05 pH
  • EC/TSD Accuracy: 2% Full scale
  • Temp Accuracy: ±0.5°C / ±1°F
  • Temperature Compensation: Automatic with ß=0.0 to 2.4%/°C
  • Calibration automatic, 1 point for EC and 1 or 2 points for pH
  • TDS Factor: 0.45 to 1.00 (conv.)
  • Probe: Mi60P (replaceable)
  • Environment: 0 to 50°C; 100% RH max.
  • Battery Type: 4 x 1.5V; IEC LR44, A76 (included)
  • Battery Life: approx. 100 hours of use
  • Auto-off after 8 minutes of non-use
  • Dimensions: 7.9 inches × 1.5 inches (diameter)
  • Weight: 3.5 ounces

Milwaukee MW804 Manual


All pH sensors have a limited life and response time gets longer with age. Properly maintaining the MAX pH Tester will provide fast, accurate results for longer.

EC sensors are more robust but can still be affected by residue build up.

Here are a few tips:

  1. Always store with the cap full of buffer or storage solution MA9015, not water.
  2. Clean your Tester regularly by soaking in cleaning solution MA9016.
  3. Calibrate after cleaning and/or storage before testing to adjust for changes in the pH and EC sensor.
  4. Gently stir the MAX Tester in the sample for a faster result.
  5. Rinse in water after every test.
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