Bluelab pH Pen

Quick, Dependable pH Checks for Any Nutrient Reservoir, Handheld

Plants can only take up nutrients when the solution sits in the right pH range, and pH drifts as plants feed. The Bluelab pH Pen measures pH 0.0–14.0 with ±0.1 accuracy, plus temperature, so you can confirm and correct your solution in seconds. Automatic temperature compensation keeps readings consistent as solution temperature changes.

The compact pen suits hobby growers making their first nutrient adjustments and serves as a reliable backup meter in larger operations. Pair it with the Bluelab Conductivity Pen to check both pH and nutrient strength.

Key Features & Benefits

• Double-junction pH probe — built for accurate measurement in nutrient solution.
• 2-point calibration — uses pH 7.0 and pH 4.0 (or pH 10.0) solutions, with a 30-day reminder.
• Waterproof and floats — survives splashes and floats if dropped into a tank.
• Backlit display — reads pH and °C or °F clearly in dim grow spaces.

Who Should Use the Bluelab pH Pen

Home growers who want a simple, reliable pH reading, and commercial teams who need a portable pH check alongside fixed monitors. It works in solutions of 0.2 EC and above.

About Bluelab pH Pen

The Bluelab pH Pen is a compact pH and temperature meter that runs on 1x AAA battery. It ships with single-use pH 7.0, pH 4.0 and KCl storage solution sachets and carries a 1-year limited warranty.

Frequently Asked Questions

Why does nutrient solution pH matter?

pH controls how soluble, and therefore how available, each nutrient is to plant roots. If the solution becomes too acidic or too alkaline, plants cannot access some nutrients even when they are present. Checking pH regularly lets you correct drift before it affects growth.

How do I calibrate the Bluelab pH Pen?

Calibrate with two points: pH 7.0 first, then pH 4.0 (or pH 10.0). The pen shows a 30-day reminder so you know when to recalibrate. Fresh calibration solution gives the most accurate result.

What is a double-junction pH probe?

A double-junction probe has two reference chambers between the sensor and the solution being measured. This extra barrier slows contamination of the reference, which helps the probe hold calibration in nutrient-rich solutions.

Does the pH Pen measure EC or ppm?

No. The pH Pen measures pH and temperature only. For nutrient strength, use the Bluelab Conductivity Pen, or choose the pH and Conductivity Starter Pack, which includes both pens.