Bluelab pH Pen, Waterproof
Product details
| Management number | 250626030 | Release Date | 2026/09/17 | List Price | US$39.98 | Model Number | 250626030 | ||
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Know your pH in seconds with a pen that thrives in the grow room
The Bluelab pH Pen reads pH from 0.0 to 14.0 at 0.1 resolution and shows solution temperature on the same backlit screen. It is fully waterproof (not just splash-resistant) and floats if it lands in your reservoir. Bluelab builds it in New Zealand with a double-junction probe for longer life in nutrient-heavy solutions, and it ships with pH 4.0, pH 7.0, and KCl storage solution so you can calibrate and start measuring the same day.
- Single-junction probes clog fast in nutrient solutions
- Drift out of calibration within days
- Water-resistant at best, dead after one drop in the reservoir
- No calibration reminder, so you forget and run on bad data
- No temperature compensation, readings shift with heat
- Calibration solutions sold separately, adding $10+ on day one
- Double-junction probe resists contamination from nutrients
- 2-point calibration (pH 4.0 and 7.0) holds accuracy to ±0.1 pH
- Fully waterproof and floats, built for daily reservoir use
- 30-day calibration reminder built into the firmware
- Automatic temperature compensation adjusts readings in real time
- pH 4.0, pH 7.0, and KCl storage solution included in the box
Double-junction pH probe ±0.1 pH
Two reference junctions instead of one. The outer junction takes the beating from nutrient salts so the inner junction stays clean, which means stable readings for longer before the probe wears out.
Waterproof and floats
Not splash-rated, fully waterproof. If it slips into the reservoir, it floats on the surface instead of sinking to the bottom.
Automatic temperature compensation
pH readings shift with temperature. The pen measures solution temp (0 to 50°C) and corrects the pH value automatically, so a reading from a warm reservoir is just as reliable as one from a cool mixing bucket.
Backlit LCD with hold function
The screen lights up for reading in dim grow rooms. Press the hold button to lock the display so you can pull the pen out and read at eye level.
30-day calibration reminder
A built-in timer tracks the days since your last calibration and alerts you when it is time to recalibrate. No guessing, no forgetting.
Auto-off and low battery warning
The pen shuts itself off after inactivity to preserve the single AAA battery. A low-battery icon appears before it dies so you are never caught mid-reading.
How to set up and use your pH Pen
Hydrate the probe
Remove the storage cap and soak the probe tip in the included KCl storage solution for 24 hours before first use. This activates the glass membrane so it can read pH accurately.
Calibrate with two solutions
Dip the probe in the pH 7.0 sachet, press the calibration button, then repeat in the pH 4.0 sachet. A confirmation indicator on screen tells you the calibration succeeded.
Take your reading
Submerge the probe in your nutrient solution or reservoir and wait for the display to stabilize. The reading shows pH and temperature simultaneously on the backlit screen.
Rinse, store, repeat
After each use, rinse the probe tip in clean water, then replace the storage cap with a few drops of KCl solution inside. This keeps the probe hydrated and extends its working life.
- Bluelab pH Pen (waterproof)
- pH 7.0 calibration solution sachet
- pH 4.0 calibration solution sachet
- KCl probe storage solution
- 1x AAA battery (installed)
- Quick-start guide
- Bluelab Conductivity Pen: Measures EC/PPM so you can check nutrient strength alongside pH
- Bluelab Probe Care Kit (pH): Extra calibration sachets, KCl solution, and cleaning tools for ongoing maintenance
- Bluelab KCl Storage Solution (250ml): Larger bottle for long-term probe storage between uses
Questions? We're easy to reach.
Happy Hydro has been serving growers since 2006. Call or email us before you order, after you order, or any time something comes up. When you're happy, we're happy.
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