Description
A fresh sensor that keeps your OnePen reading true
The Bluelab OnePen Replacement Probe is the genuine spare sensor for the Bluelab OnePen, the 3-in-1 meter that reads pH, conductivity (EC) and temperature from a single dip. Everything that wears lives in the probe: a double-junction pH probe, titanium EC electrodes and the temperature sensor, in an IP68 waterproof and dustproof body. When it ages you change this part and keep the pen, its display and its Bluetooth link to the Edenic app.
Key Benefits
- All three readings restored – pH, EC and temperature in one swap
- Genuine Bluelab part – the OnePen flags an incorrect probe, so only an official probe will do
- Double-junction pH probe with 0.01 pH resolution and ±0.05 pH accuracy at 25 °C
- Titanium EC electrodes resist corrosion and read 0–10.0 EC
- IP68 rated once fitted – safe at the reservoir edge
- Quick to fit – an alignment arrow and threaded collar, no tools
When Should the Probe Be Replaced?
Bluelab put the average life of a OnePen probe at about 18 months, depending on how well it is cleaned and stored. The signs are a pH reading that will not calibrate, drifts or settles slowly after a proper clean and a 24-hour KCl soak, or an EC reading that no longer matches 2.77 EC standard solution. A meter that reads wrong leads to wrong corrections: pH out of range costs nutrient uptake, and an EC that reads low ends in overfeeding and tip burn.
How to Use
- Remove the storage cap and hold the pen upside down so the batteries stay in place.
- Unscrew the threaded collar and pull the old probe straight out of the pen body.
- Fit the new probe with its protective cap removed, lining the arrow up with the notch, and push it fully home.
- Tighten the threaded collar fully to restore the waterproof seal.
- Calibrate pH at 7.0 then 4.0, and check EC in 2.77 EC standard solution.
- Store with a few drops of KCl storage solution on the sponge in the cap; never soak the EC electrodes in KCl and never use RO, distilled or deionised water.
Technical Specifications
- Fits: Bluelab OnePen only
- Sensors: double-junction pH probe, titanium conductivity electrodes, temperature sensor
- pH: 0.0–14.0, resolution 0.01, accuracy ±0.05 at 25 °C
- Conductivity: 0–10.0 EC or mS/cm (resolution 0.01, accuracy ±0.1), 0–100 CF, 0–5000 ppm (500 scale), 0–7000 ppm (700 scale)
- Temperature: 0–50 °C / 32–122 °F, accuracy ±1
- Calibration: pH two-point (7.0 and 4.0, or 7.0 and 10.0); EC factory calibrated, checked against 2.77 EC solution
- Rating: IP68 water and dust ingress
- Average life: about 18 months with correct care (Bluelab)
- Warranty: 6 months
- Bluelab part code: PROBONE
Frequently Asked Questions
Will it fit the pH PenPlus or another Bluelab pen?
No. It fits the Bluelab OnePen only. The pH PenPlus takes the Bluelab pH ProbePlus, and the standard pH Pen and Conductivity Pen have sealed probes.
Do I need to recalibrate after fitting it?
Yes. Calibrate pH at 7.0 then 4.0 before the first reading, and check the EC reading in 2.77 EC standard solution.
How long will the new probe last?
Bluelab quote an average of about 18 months. Cleaning it regularly and keeping the pH bulb wet with KCl storage solution are what make the difference.
Works Well With
