Bluelab Combo Meter – Digital pH, EC and Temperature Meter for Hydroponics

The Bluelab Combo Meter is a professional portable testing instrument designed to accurately measure pH, electrical conductivity (EC), and temperature in hydroponic nutrient solutions. Combining three essential measurements in one convenient device, it helps growers monitor nutrient concentration, water quality, and conditions that influence nutrient uptake.

Equipped with a replaceable double-junction pH probe and a factory-calibrated conductivity/temperature probe, the Combo Meter provides reliable measurements in nutrient reservoirs, irrigation water, and runoff solutions.

Its backlit digital display, simple push-button controls, and battery-powered design make it suitable for testing multiple reservoirs and growing areas.

Ideal for hydroponic cultivation, indoor growing facilities, commercial greenhouses, and professional horticulture, the Bluelab Combo Meter offers straightforward operation without requiring Wi-Fi connectivity or a smartphone application.

Accurate pH, EC and Temperature Measurements

Monitoring nutrient solution conditions helps growers maintain appropriate feeding concentrations and identify changes that may affect plant development.

The Bluelab Combo Meter measures three essential parameters.

pH Measurement

The replaceable double-junction pH probe measures solution acidity and alkalinity across a range of 0.0 to 14.0 pH, with an accuracy of ±0.1 pH at 25°C.

Regular pH testing helps growers determine whether their nutrient solution is within the recommended range for nutrient availability.

Electrical Conductivity (EC)

The conductivity probe measures dissolved ion concentration, providing a useful indication of nutrient solution strength.

The Combo Meter supports multiple conductivity scales, including EC, CF, ppm 500 (TDS), and ppm 700.

Unlike the pH probe, the conductivity probe is factory-calibrated and does not require routine calibration.

Temperature Measurement

The integrated temperature sensor measures nutrient solution temperature from 0 to 50°C (32 to 122°F).

Temperature can be displayed in Celsius or Fahrenheit, allowing growers to identify changes in reservoir conditions.

Key Features and Benefits

• Three-in-One Testing: Measures pH, electrical conductivity, and temperature using one portable instrument.

• Replaceable pH Probe: Features a double-junction electrode with a standard BNC connection.

• Factory-Calibrated Conductivity Probe: Ready for use without additional conductivity calibration.

• Backlit Digital Display: Provides clear readings in different lighting conditions.

• Two-Point pH Calibration: Supports calibration using pH 7.0 and pH 4.0 reference solutions.

• 30-Day Calibration Reminder: Helps growers maintain a consistent pH calibration schedule.

• Multiple Conductivity Scales: Displays EC, CF, ppm 500, or ppm 700 values.

• Long Probe Cables: Two-metre (6.6 ft) cables provide convenient access to deeper reservoirs.

• Portable Battery-Powered Design: Allows measurements in multiple growing areas without a permanent power connection.

• Low Battery and Measurement Indicators: Help identify battery replacement needs and readings outside the supported measurement range.

How to Use the Bluelab Combo Meter

The Combo Meter is designed for convenient testing of hydroponic nutrient solutions.

Step 1 – Prepare the Probes

Remove the protective cap from the pH probe and ensure both sensors are clean. Verify that the pH probe has been calibrated according to Bluelab's recommendations.

Step 2 – Immerse the Sensors

Place the pH and conductivity/temperature probes into the nutrient solution, following the manufacturer's immersion guidelines.

Step 3 – Measure pH

Select the pH measurement function and allow the reading to stabilize before recording the value.

Step 4 – Measure Conductivity and Temperature

Select the preferred conductivity scale and read the nutrient concentration indicator. Check the solution temperature in Celsius or Fahrenheit.

Step 5 – Rinse and Store

After testing, rinse the probes with clean water. Replace the pH probe storage cap with the appropriate KCl storage solution to keep the electrode hydrated.

Important: The standard Combo Meter is designed for testing liquids. Direct substrate pH measurements require a compatible Bluelab Soil pH Probe, available separately.

Technical Specifications

Measurement accuracy specifications are stated at 25°C (77°F).

What's Included with the Bluelab Combo Meter?

The manufacturer's standard package includes:

• 1 × Bluelab Combo Meter with conductivity/temperature probe
• 1 × Bluelab pH Probe
• 1 × Bluelab pH Probe Holder with Suction Cup
• 1 × 18 mL Bluelab pH 7.0 Calibration Solution Sachet
• 1 × 18 mL Bluelab pH 4.0 Calibration Solution Sachet
• 1 × 18 mL Bluelab KCl Storage Solution Sachet

The instrument operates using two AAA alkaline batteries.

Calibration and Probe Maintenance

Proper maintenance helps preserve measurement accuracy and extend the useful life of the sensors.

The pH probe requires regular cleaning and calibration using fresh pH 7.0 and pH 4.0 reference solutions. A built-in 30-day reminder helps users keep track of calibration requirements.

The electrode must remain hydrated during storage. Use Bluelab KCl storage solution in the protective cap and avoid storing the probe in distilled, deionized, or reverse-osmosis water.

The conductivity/temperature probe should also be cleaned regularly to remove fertilizer residue and mineral deposits. Since it is factory-calibrated, routine EC calibration is not required.

If the pH electrode becomes damaged or fails to calibrate despite proper cleaning and hydration, it can be replaced separately without purchasing another Combo Meter.

Frequently Asked Questions About the Bluelab Combo Meter

What does the Bluelab Combo Meter measure?

The Bluelab Combo Meter measures pH, electrical conductivity (EC), and temperature in nutrient solutions, irrigation water, and runoff. It supports EC, CF, ppm 500, and ppm 700 conductivity scales.

Does the Bluelab Combo Meter require calibration?

The pH probe requires regular calibration using appropriate reference solutions. The conductivity/temperature probe is factory-calibrated and does not require routine calibration.

Can the Bluelab Combo Meter measure soil pH?

The standard package includes a pH probe for liquid measurements. However, the meter is compatible with the separately available Bluelab Soil pH Probe for direct measurements in suitable growing media.

Does the Combo Meter connect to the Edenic app?

No. The standard Bluelab Combo Meter does not feature Bluetooth or Wi-Fi connectivity. Growers requiring app connectivity may prefer the Bluelab OnePen.

Can the pH probe be replaced?

Yes. The Combo Meter uses a replaceable Bluelab pH Probe with a BNC connector, allowing the sensor to be replaced when necessary.

What is the difference between the Bluelab Combo Meter and Guardian Monitor Wi-Fi?

The Combo Meter is a portable, battery-powered instrument used for individual measurements. The Guardian Monitor Wi-Fi is designed for continuous reservoir monitoring, with a permanent display, programmable alarms, and remote access through Edenic.