Bluelab pH PenPlus

The Bluelab pH PenPlus is a precision handheld pH and temperature meter built for the demands of daily use in hydroponic and growing environments. Bluelab's reputation for accuracy is well established in the professional growing industry, and the PenPlus carries that standard in a compact, waterproof form factor designed to hold up to regular handling across a working grow space.

Where the PenPlus stands apart from comparable meters is its replaceable probe design. The probe is the component that degrades over time in any pH meter, and rather than requiring the entire unit to be replaced when accuracy declines, the PenPlus allows the probe to be swapped out in seconds via a screw-cap connection, no tools required. The double-junction probe improves resistance to contamination from nutrient solutions, extending its working life compared to single-junction alternatives, and the KCl-filled silicone cap with internal sponge keeps it hydrated and ready between uses.

Calibration is a straightforward two-point process with a 30-day on-screen reminder to keep accuracy consistent over time. The hold-reading function freezes the display for easy recording, the backlit screen is legible in low light, and the IP68 rating means the unit is fully dustproof and waterproof. Temperature is displayed in °C or °F. Auto-off extends battery life during daily use across a growing area.

A note on pH probe care and warranty: pH probes and pH pens are precision scientific instruments and require consistent care and maintenance to provide accurate readings and remain within warranty. Please read the full instruction booklet included with your instrument before use.

pH probes and pens (without replaceable probes) are electrical sensors and are considered consumable items, in the same way that growing media and nutrients are replaced over time. The live charge in the sensing electrode degrades naturally with use, and hydroponic nutrient solutions accelerate this process significantly compared to other applications. Probes and non-replaceable pens carry a 6-month warranty from the date of purchase. Proof of purchase is required for any warranty claim.

With correct care, a pH probe can last considerably longer than 6 months. Without it, the electrode can fail well within that window. The two most important rules are simple: always rehydrate the probe in storage solution before use, and always store the probe in storage solution when not in use. In-tank monitors are the exception to the storage rule, as the probe remains submerged during operation. Storage solution is available in stores and should be considered an essential part of your pH monitoring setup. If it dries, it dies.