Monitor water quality quickly and accurately with the Milwaukee EC59 PRO Waterproof Conductivity, TDS and Temperature Meter.

Designed for convenient everyday water testing, this compact 3-in-1 digital meter measures electrical conductivity (EC), total dissolved solids (TDS) and temperature, making it an excellent choice for aquariums, aquaculture, hydroponics, agriculture and general water quality monitoring.

The Milwaukee EC59 PRO combines a waterproof IP65-rated housing with automatic temperature compensation (ATC), automatic calibration and a replaceable measurement probe.

Its dual-level LCD display allows you to view conductivity or TDS measurements alongside the water temperature, helping you monitor important water quality parameters quickly and conveniently.

With an EC measurement range of 0–3999 µS/cm and a TDS range of 0–2000 ppm, the EC59 PRO is particularly suitable for applications requiring low-to-medium conductivity water measurements.

Whether you're maintaining an aquarium, monitoring aquaculture systems, checking hydroponic nutrient solutions or testing water treatment processes, the Milwaukee EC59 PRO provides a practical and reliable water testing solution.

Key Features & Benefits

• 3-in-1 Water Quality Testing: Measures electrical conductivity (EC), total dissolved solids (TDS) and temperature using one compact instrument.

• Conductivity Measurement: Measures EC from 0 to 3999 µS/cm for monitoring dissolved ionic content in water.

• TDS Measurement: Measures total dissolved solids from 0 to 2000 ppm.

• Automatic Temperature Compensation (ATC): Automatically compensates conductivity measurements for temperature variations.

• Simultaneous Temperature Display: Displays water temperature alongside EC or TDS readings on the dual-level LCD.

• Waterproof IP65 Construction: Designed to withstand water exposure and splashes during routine testing.

• Replaceable Measurement Probe: Features a replaceable Milwaukee Mi59P probe, extending the useful life of the instrument.

• Automatic Calibration: Simple one-point calibration using the appropriate conductivity calibration solution.

• Adjustable TDS Conversion Factor: Allows the meter to accommodate different TDS conversion scales.

• Stability Indicator: Helps identify when readings have stabilised.

• Hold Function: Freezes the displayed reading for convenient recording.

• Compact & Portable: Lightweight pocket-sized design suitable for everyday testing and fieldwork.

• Battery Powered: Approximately 100 hours of operation from four LR44 batteries.

Ideal Applications

The Milwaukee EC59 PRO is suitable for a wide range of water quality monitoring applications.

Aquariums & Fish Tanks

Monitor electrical conductivity and TDS to help assess changes in dissolved ionic content and overall aquarium water conditions.

Regular EC and TDS measurements can help identify changes in water composition, making the EC59 PRO a useful addition to an aquarium water testing kit.

Aquaculture & Fish Farming

Monitor conductivity and dissolved solids in fish tanks, hatcheries and aquaculture systems.

EC measurements can help identify changes in water chemistry and support routine water quality management in commercial aquaculture operations.

Hydroponics

Electrical conductivity is an important measurement in hydroponic growing systems.

The EC59 PRO allows growers to monitor nutrient solution conductivity and check whether nutrient concentrations remain within their desired operating range.

Monitoring EC alongside temperature helps provide a better understanding of changing nutrient solution conditions.

Agriculture & Horticulture

Suitable for monitoring irrigation water, growing solutions and other agricultural water samples.

Water Treatment

Measure conductivity and TDS as part of routine water quality monitoring and treatment processes.

Laboratory & General Water Testing

A convenient portable instrument for checking conductivity, dissolved solids and temperature in a variety of water samples.

Understanding EC and TDS Measurements

The Milwaukee EC59 PRO measures electrical conductivity (EC) and converts this measurement into an estimated total dissolved solids (TDS) value.

Although EC and TDS are closely related, they are not exactly the same measurement.

Electrical Conductivity (EC)

EC measures the ability of water to conduct electricity, which is influenced by the concentration of dissolved ions.

Readings are displayed in microsiemens per centimetre (µS/cm).

Conductivity monitoring is particularly useful in aquaculture, hydroponics and water treatment applications.

Total Dissolved Solids (TDS)

TDS is an estimate of the concentration of dissolved substances in water, normally displayed in parts per million (ppm).

The EC59 PRO calculates TDS from its conductivity measurement using a selectable conversion factor.

Different conversion factors can produce different TDS readings from the same EC measurement. The appropriate scale should therefore be selected according to your application and testing requirements.

Automatic Temperature Compensation (ATC)

Water conductivity changes with temperature, which can affect measurement results.

The Milwaukee EC59 PRO incorporates automatic temperature compensation to adjust conductivity measurements according to the temperature of the sample.

The temperature is displayed separately on the secondary LCD, allowing you to monitor both parameters during testing.

The temperature compensation coefficient can also be adjusted to suit different measurement requirements.

Replaceable Milwaukee Mi59P Probe

One of the main advantages of the Milwaukee EC59 PRO is its replaceable Mi59P conductivity probe.

Over time, measurement probes can become contaminated or deteriorate through regular use. The replaceable probe design allows you to change the sensing component without replacing the entire instrument.

Benefits include:

• Extends the useful working life of the meter.

• Allows replacement of a worn or damaged probe.

• Reduces the need to purchase a completely new instrument.

• Provides a practical solution for regular water quality monitoring.

The replacement probe is the Milwaukee Mi59P, compatible with the EC59 and EC60 testers.

Technical Specifications

Specification	Details
Brand	Milwaukee Instruments
Model	EC59 PRO
Measurement Parameters	EC, TDS & Temperature
EC Measurement Range	0–3999 µS/cm
TDS Measurement Range	0–2000 ppm
Temperature Range	0.0–60.0°C / 32.0–140.0°F
EC Resolution	1 µS/cm
TDS Resolution	1 ppm
Temperature Resolution	0.1°C / 0.1°F
EC Accuracy	±2% Full Scale
TDS Accuracy	±2% Full Scale
Temperature Accuracy	±0.5°C / ±1°F
Calibration	Automatic, 1-point
EC Calibration Solution	1413 µS/cm
Temperature Compensation	Automatic (ATC)
Temperature Compensation Coefficient	Adjustable, β = 0.0–2.4%/°C
TDS Conversion Factor	Adjustable
Probe	Milwaukee Mi59P
Probe Type	Replaceable conductivity/TDS probe
Waterproof Rating	IP65
Display	Dual-level LCD
Battery Type	4 × 1.5V LR44 / A76
Battery Life	Approximately 100 hours
Automatic Power-Off	After 8 minutes of inactivity
Dimensions	Approximately 200 × 38 mm
Weight	Approximately 100 g

Easy Automatic Calibration

The Milwaukee EC59 PRO features automatic one-point calibration to help maintain reliable conductivity measurements.

Calibration is performed using a suitable conductivity calibration solution.

For the EC59 PRO, the recommended calibration solution is:

1413 µS/cm Conductivity Calibration Solution

The meter automatically recognises the calibration point and completes the calibration process.

Regular calibration is recommended, particularly after replacing the probe, cleaning the sensor or when measurement accuracy is especially important.

Because TDS is calculated from conductivity using a conversion factor, separate TDS calibration is not required.

Probe Maintenance & Care

Correct probe maintenance helps maintain measurement reliability and extend the working life of the instrument.

We recommend:

• Rinse the probe with fresh water after every use.

• Remove any visible nutrient or mineral deposits.

• Clean the probe periodically using a suitable conductivity probe cleaning solution.

• Avoid allowing nutrient solutions or other residues to dry on the sensing surfaces.

• Calibrate regularly using fresh 1413 µS/cm conductivity calibration solution.

• Replace the Mi59P probe if it becomes damaged or measurement performance deteriorates.

• Fit the protective cap when the instrument is not in use.

Recommended Accessories

The following Milwaukee accessories are suitable for maintaining and calibrating the EC59 PRO:

• Milwaukee MA9061: 1413 µS/cm conductivity calibration solution.

• Milwaukee M10031B: 1413 µS/cm calibration solution sachets.

• Milwaukee MA9016: Cleaning solution.

• Milwaukee M10000B: Rinse solution sachets.

• Milwaukee Mi59P: Replacement EC/TDS probe.

What's Included?

The standard Milwaukee EC59 PRO package includes:

• Milwaukee EC59 PRO conductivity/TDS/temperature meter.

• Replaceable Mi59P measurement probe.

• Protective probe cap.

• 1413 µS/cm calibration solution sachet.

• Four LR44 batteries.

• Instruction manual.

• Protective packaging.

Please check the supplied packaging configuration against your actual stock before publishing this list.

Why Buy from GroAqua?

GroAqua supplies specialist water quality monitoring equipment for aquariums, aquaculture, hydroponics and water treatment applications.

From everyday aquarium water testing to professional water monitoring equipment, we help customers find practical solutions for maintaining water quality.

The Milwaukee EC59 PRO is an excellent choice for customers looking for a compact, waterproof conductivity and TDS meter with the added convenience of temperature measurement and a replaceable probe.

Order your Milwaukee EC59 PRO Waterproof EC/TDS/Temperature Meter from GroAqua today.