Bluelab pH Pen

Product detailed description

The Bluelab pH Pen is a pocket pH metre for nutrient solutions designed for growers who want to keep nutrient uptake under control. Simply immerse the probe into the tank and within moments you will know if the solution is within the correct range – pH controls how many nutrients the plant can absorb.

Why it pays off

You will notice a slight pH shift before it affects the plant. The metre measures in the range 0.0-14.0 pH with an accuracy of ±0.1 pH and a resolution of 0.1 pH, giving you reliable information about the solution's acidity.

• Floats on the surface and is waterproof – if the pen falls into the tank, nothing happens and you can easily find it again.
• Backlit display lets you read it even in a dim grow tent.
• Two-point calibration at pH 4.0 and 7.0 ensures accuracy that cheap single-point testers cannot offer.
• Powered by one AAA battery (included); automatic shut-off after 4 minutes and low battery indicator save energy.
• One-year warranty.

Calibration and probe care

Calibrate the metre using two-point calibration solutions pH 4.0 and pH 7.0; after 30 days it will prompt you to recalibrate. Never let the glass probe dry out – always measure and store the pen in a solution with conductivity of at least 0.2 EC. Calibration solutions pH 4.0 and pH 7.0 are essential daily accessories.

Which pH pen to choose

The Bluelab pH Pen is the basic choice for solution measurement with a built-in (non-replaceable) probe. If you want to replace only the probe after wear instead of the whole device, choose the Bluelab pH Pen Plus. For measuring directly in substrate and root zones, use the Bluelab pH Pen for soil version with a robust tip.

Monitor pH mainly when mixing nutrient solutions. Typically, hydroponics and coco substrates maintain pH around 5.5-6.5, while soil is usually 6.0-7.0 – always verify the precise range for your crop and growth stage. Prepare the solution with fertilisers and then adjust the pH.

Specifications

• pH: range 0.0-14.0, resolution 0.1 pH, accuracy ±0.1 pH (at 25 °C)
• Temperature: 0-50 °C, accuracy ±1 °C
• Calibration: two-point (pH 4.0 and 7.0), 30-day reminder
• Power supply: 1x AAA alkaline battery (approx. 350 hours), automatic shut-off after 4 minutes, low battery indicator
• Water resistance: fully waterproof body, pen floats on surface
• Display: backlit
• Warranty: 1 year
• Package contents: Bluelab pH Pen, single-use calibration solution sachets pH 4.0 and pH 7.0

Frequently asked questions

How often should the Bluelab pH Pen be calibrated?

Calibrate using two-point solutions pH 4.0 and pH 7.0. The device has a built-in 30-day reminder that alerts you when recalibration is due. Regular calibration is the only way to keep measurements accurate – the probe naturally changes characteristics over time and without recalibration values would drift.

How should I store the probe to ensure durability?

Never let the glass pH probe dry out. Always measure and store the Bluelab pH Pen in a solution with conductivity of at least 0.2 EC, never dry or in distilled water. A dried-out probe loses accuracy and lifespan. Operating and storage temperature is 0-50 °C.

What is the purpose of a pH metre in cultivation?

pH determines how well a plant absorbs individual nutrients. When the value deviates from the ideal range, nutrient uptake is blocked (lockout) and the plant suffers despite sufficient nutrients. Measuring the nutrient solution pH prevents this and keeps growth and yield under control.