The Milwaukee MW801 PRO is a portable, professional water-quality meter that measures pH, electrical conductivity (EC) and total dissolved solids (TDS) using one integrated combination probe.

Designed for freshwater applications, aquariums, aquaculture, hydroponics and nutrient-solution monitoring, the MW801 makes it easier to check three important water parameters without carrying separate instruments.

Its replaceable SE600 combination probe incorporates pH, EC/TDS and temperature-sensing components. Automatic temperature compensation helps account for temperature variation during EC and TDS measurements, while simple manual calibration makes routine maintenance straightforward.

With a low-range EC measurement capability of up to 1,990 µS/cm and TDS measurement up to 1,990 ppm, the MW801 PRO is particularly suitable for applications where monitoring relatively low dissolved-solids concentrations is important.

Key Features

• Three measurements in one instrument – measures pH, electrical conductivity (EC) and total dissolved solids (TDS).

• Low-range EC measurement – measures conductivity from 0 to 1,990 µS/cm.

• Low-range TDS measurement – measures dissolved-solids levels from 0 to 1,990 ppm.

• Replaceable SE600 combination probe – combines pH, EC/TDS and temperature-sensing functions in one probe.

• Automatic Temperature Compensation (ATC) – compensates for temperature variation during EC and TDS measurements from 0 to 50°C.

• Manual one-point calibration – straightforward calibration for pH and EC/TDS.

• Large, easy-to-read display – clearly displays measurement results.

• Portable design – suitable for routine testing in the field, laboratory or workplace.

• Supplied with calibration solutions and battery – ready for setup and use.

Three Important Water Measurements in One Meter

The MW801 PRO combines three useful water-quality measurements in a single instrument.

pH – Acidity and Alkalinity

pH indicates how acidic or alkaline water is. Monitoring pH is important for aquarium management, aquaculture, hydroponics and water treatment, as changes can affect aquatic organisms, nutrient availability and water chemistry.

The MW801 measures pH across a range of 0.0 to 14.0 pH.

EC – Electrical Conductivity

Electrical conductivity indicates how readily water conducts an electrical current. It is influenced by the concentration of dissolved ions, including salts and minerals.

EC monitoring is useful when checking water sources, monitoring nutrient solutions and observing changes in dissolved ionic content.

The MW801 measures EC from 0 to 1,990 µS/cm.

TDS – Total Dissolved Solids

TDS provides an estimated measurement of dissolved-solids concentration, displayed in parts per million (ppm).

It is commonly used in water treatment, aquariums and hydroponic applications to monitor changes in dissolved-solids levels.

The MW801 measures TDS from 0 to 1,990 ppm.

One Combination Probe – Three Measurements

The MW801 PRO is supplied with the SE600 combination probe, which incorporates pH, EC/TDS and temperature-sensing components.

Using one probe for all three measurements makes routine testing more convenient and reduces the need to handle multiple separate electrodes.

The SE600 is replaceable, allowing the probe to be changed when its performance deteriorates or it reaches the end of its service life.

The probe features a double-junction pH electrode design and a fibre junction intended to help reduce contamination when testing nutrient and fertiliser solutions.

Automatic Temperature Compensation

Temperature affects electrical conductivity, so readings need to account for changes in sample temperature.

The MW801 features automatic temperature compensation from 0 to 50°C for EC and TDS measurements. This helps provide more consistent readings when testing samples at different temperatures.

Simple Calibration

The MW801 PRO uses manual one-point calibration for pH and EC/TDS.

For pH calibration, Milwaukee recommends using an appropriate buffer solution, such as pH 7.01 for measurements around neutral pH.

For EC/TDS calibration, use the appropriate standard:

• M10031B – 1,413 µS/cm conductivity calibration solution

• M10032B – 1,382 ppm TDS calibration solution

The meter's EC and TDS measurements are linked internally. Calibrating in either EC or TDS mode automatically calibrates the other measurement mode.

Suitable Applications

The Milwaukee MW801 PRO is suitable for a range of water-quality monitoring tasks, including:

• Aquariums: monitor pH, conductivity and TDS as part of routine water-quality checks.

• Aquaculture: monitor changes in water chemistry and dissolved ionic content.

• Hydroponics: check pH and nutrient-solution conductivity to support nutrient management.

• Aquaponics: monitor important water parameters in integrated fish and plant systems.

• Water treatment: assess changes in dissolved-solids levels and conductivity.

• Freshwater testing: measure pH, EC and TDS in freshwater samples.

For aquariums and aquaculture, the MW801 is best used as part of a wider water-testing routine. It does not measure parameters such as ammonia, nitrite, nitrate or dissolved oxygen.

Probe Care and Maintenance

The combination probe is an important component of the MW801 and needs regular care to maintain reliable performance.

Recommended maintenance:

• Rinse the probe with clean water after testing.

• Keep the pH sensing element hydrated using suitable electrode storage solution.

• Do not store the probe in distilled or deionised water.

• Clean the electrode periodically using an appropriate electrode cleaning solution.

• Calibrate after cleaning and whenever readings become questionable.

• Replace the probe when response time or measurement performance deteriorates.

Milwaukee recommends MA9015 storage solution for pH electrode storage and MA9016 cleaning solution for electrode maintenance.

Technical Specifications

Specification	Details
Model	Milwaukee MW801 PRO
Measurements	pH, EC and TDS
pH range	0.0–14.0 pH
pH resolution	0.1 pH
pH accuracy	±0.2 pH
EC range	0–1,990 µS/cm
EC resolution	10 µS/cm
EC accuracy	±2% full scale
TDS range	0–1,990 ppm
TDS resolution	10 ppm
TDS accuracy	±2% full scale
TDS conversion factor	0.5
Calibration	Manual, one point
Temperature compensation	Automatic, 0–50°C
Probe	SE600 combination pH/EC/TDS probe
Probe cable	1 m
Operating environment	0–50°C; maximum 95% RH
Power supply	1 × 9V alkaline battery
Battery life	Approximately 150 hours
Meter dimensions	143 × 80 × 32 mm
Weight	Approximately 220 g, including battery

Supplied With

• Milwaukee MW801 PRO meter

• SE600 combination pH/EC/TDS probe

• 20 mL pH 7.01 calibration solution

• 20 mL 1,413 µS/cm conductivity calibration solution

• 20 mL 1,382 ppm TDS calibration solution

• 9V alkaline battery

• Instruction manual

A Versatile 3-in-1 Meter for Water Quality Monitoring

The Milwaukee MW801 PRO combines pH, EC and TDS testing in one portable instrument. Its replaceable SE600 probe, automatic temperature compensation and straightforward calibration make it a practical choice for aquarium keepers, aquaculture professionals and hydroponic growers.

Choose the MW801 PRO when you need a reliable way to monitor three important water parameters without carrying separate meters.