Bluelab OnePen

Product detailed description

Bluelab OnePen is a pocket 3-in-1 combined metre for growers who want to monitor all key solution parameters with one pen - pH, conductivity (EC/PPM), and temperature. All values are displayed simultaneously on the screen and sent via Bluetooth to the Edenic app.

Why it pays off

• The most accurate pH of all Bluelab pens - accuracy ±0.05 pH and resolution 0.01 pH (standard pens have ±0.1). You can detect even slight shifts.
• Three measurements in one - pH (0-14), conductivity in EC (0-10), CF, PPM 500 (0-5000) and PPM 700 (0-7000), and temperature (0-50 °C).
• Replaceable probe with dual junction for pH and titanium electrodes for EC, plus probe status indicator.
• Bluetooth and Edenic app for data sharing and real-time updates.
• IP68 rating - dustproof and waterproof body.
• Two-year warranty on the device (6 months on replacement probe).

Calibration and probe care

Calibrate pH with two-point solutions pH 4.0 and pH 7.0; verify conductivity against EC 2.77 standard. The package includes a cleaning brush, single-use pH 4.0 and pH 7.0 sachets, and KCl storage solution. Keep the probe hydrated in KCl storage solution and never let it dry out. For comprehensive maintenance, use the care kit for combined pH/EC metres.

Who is OnePen for

Choose OnePen if you want a pocket 3-in-1 pen with the highest pH accuracy and Bluetooth data transfer. If you prefer a fixed dual-probe solution for your workshop, see the Bluelab Combo Metre. If you only need pH, opt for the standalone pH pen.

Why monitor pH and EC simultaneously? EC indicates the overall strength of the nutrient solution, pH determines how well the plant absorbs nutrients, and temperature affects growth rate. Monitoring all three ensures maximum plant performance without fertiliser waste.

Specifications

• pH: range 0.0-14.0, resolution 0.01 pH, accuracy ±0.05 pH (at 25 °C)
• Conductivity EC: 0-10 mS/cm, resolution 0.01, accuracy ±0.1; CF 0-100; PPM 500 (TDS) 0-5000; PPM 700 0-7000
• Temperature: 0-50 °C, accuracy ±1 °C
• Calibration: two-point pH; probe status indicator
• Probe: replaceable, dual junction for pH and titanium electrodes for EC (replacement OnePen Replacement Probe)
• Water resistance: IP68 rating (dustproof and waterproof)
• Connection: Bluetooth (Edenic app)
• Display: backlit, simultaneous pH and EC display
• Power supply: 2x AAA alkaline batteries
• Warranty: 2 years on device, 6 months on replacement probe
• Package contents: OnePen with replaceable probe, cleaning brush, single-use pH 7.0 and pH 4.0 sachets, KCl storage solution

Frequently asked questions

How accurately does OnePen measure pH?

OnePen measures pH with an accuracy of ±0.05 and a resolution of 0.01 pH, which is the best among Bluelab pocket pens (standard pens offer ±0.1). This allows you to detect even small pH shifts that other pens cannot distinguish - especially useful for sensitive crops and precisely controlled hydroponics.

What is the Bluetooth connection and Edenic app for?

Via Bluetooth, OnePen sends measured values to the Edenic app (Google Play, App Store). You can monitor and share data in real time, keep it organised in one place, and download software updates. This is useful when you want to track pH and EC development over time, not just take a one-time reading.

Is the probe replaceable?

Yes, OnePen has a replaceable probe with a dual junction for pH and titanium electrodes for conductivity measurement. When it reaches the end of its life, you can fit the replacement OnePen Replacement Probe without buying a new device. It also includes a probe status indicator to alert you to its condition.