Bluelab pH PenPlus – IP68 Waterproof Digital pH & Temperature Meter with Replaceable Probe

Unlike conventional disposable pH pens, the Bluelab pH PenPlus features a replaceable pH and temperature probe. When the probe eventually reaches the end of its service life, simply replace the probe rather than purchasing an entirely new meter—helping extend the usable life of your investment and minimise downtime.

Built for demanding grow-room environments, the PenPlus carries an IP68 waterproof and dustproof rating, making it ideal for regular use around hydroponic reservoirs, nutrient tanks, irrigation systems and other wet growing environments.

Whether you're growing in hydroponics, coco or other soilless systems, accurate pH management is essential for maintaining nutrient availability. The Bluelab pH PenPlus makes checking your nutrient solution fast, straightforward and reliable.

Why Choose the Bluelab pH PenPlus?

The pH of your nutrient solution directly affects how easily plants can access essential nutrients. Even a perfectly mixed nutrient solution can become less effective when pH moves outside the appropriate range.

The Bluelab pH PenPlus gives growers a convenient way to quickly measure both pH and temperature, helping you make informed adjustments before feeding your plants.

Its replaceable probe design also solves one of the biggest disadvantages of traditional digital pH pens: when the probe eventually wears out, you don't need to throw away the complete meter.

Simply install a compatible Bluelab pH ProbePlus and continue testing.

Replace the Probe, Not the Entire pH Pen

Every pH probe naturally wears over time.

With many traditional pH pens, once the probe reaches the end of its usable life, the entire meter needs to be replaced.

The Bluelab pH PenPlus takes a smarter approach.

Its screw-cap probe system allows the pH and temperature probe to be replaced quickly, helping extend the life of the meter while reducing unnecessary equipment replacement.

Keeping a spare replacement probe available can also mean:

• Less downtime
• Less disruption to your feeding routine
• Faster return to reliable measurements
• Better long-term value
• Continued confidence in nutrient management

The Bluelab pH PenPlus is designed around readiness—so when probe replacement is needed, you can swap in a fresh probe and get back to testing.

Key Features

• Replaceable pH and temperature probe
• Double-junction pH probe for reliable measurements
• IP68 dustproof and waterproof rating
• Measures pH from 0.0–14.0
• Measures temperature in °C or °F
• Screw-cap probe design for quick replacement
• Bright backlit digital display
• Simple 2-point calibration
• Built-in 30-day calibration reminder
• Hold-reading function
• Auto-off function to conserve battery
• KCl-filled silicone cap with internal sponge to maintain probe hydration
• Integrated lanyard
• Waterproof silicone probe cap
• Compact handheld design
• Powered by a single AAA alkaline battery

Measure pH & Temperature with One Meter

The PenPlus measures both nutrient solution pH and temperature, giving growers two important measurements from one compact handheld device.

pH Range

0.0–14.0 pH

pH Resolution

0.1 pH

pH Accuracy

±0.1 pH at 25°C

Temperature Range

0–50°C / 32–122°F

Being able to monitor both values makes routine reservoir testing faster and more convenient.

Easy 2-Point Calibration

Accurate pH measurement depends on regular calibration.

The Bluelab pH PenPlus features a straightforward 2-point calibration system and an integrated 30-day calibration reminder, helping you stay on top of routine meter maintenance.

Calibration is performed using pH calibration solutions such as:

• Bluelab pH 7.0 Calibration Solution

• Bluelab pH 4.0 Calibration Solution

Regular cleaning, calibration and correct probe storage help maintain reliable readings and maximise probe life.

Bright Backlit Display

Checking nutrient reservoirs isn't always done under ideal lighting conditions.

The PenPlus features a bright backlit display, allowing measurements to be read quickly and clearly in grow rooms, reservoir areas and other low-light environments.

The convenient hold-reading function also allows you to temporarily retain a measurement on the display, making results easier to record.

Why pH Monitoring Matters

Plants perform best when nutrients are available within an appropriate pH range.

Incorrect pH can reduce the availability of certain nutrients, potentially affecting plant development even when the nutrient solution contains the correct fertiliser concentration.

Regular pH monitoring allows growers to identify changes early and make appropriate adjustments.

The Bluelab pH PenPlus digital pH meter makes routine testing quick and straightforward, helping you maintain greater control over your feeding program.

Product Specifications

Simple Daily pH Testing

Using the Bluelab pH PenPlus is straightforward:

1. Remove the protective probe cap.

2. Place the probe into your nutrient solution.

3. Allow the reading to stabilise.

4. Check the displayed pH and temperature.

5. Make any required nutrient solution adjustments.

6. Rinse and correctly store the probe after testing.

Always keep the pH probe properly hydrated using suitable KCl storage solution.

Never allow a pH probe to dry out.

Probe Care for Long-Term Performance

Proper probe maintenance is important for obtaining reliable measurements.

For best performance:

• Clean the probe regularly

• Calibrate approximately every 30 days or as required

• Always keep the probe hydrated

• Store using appropriate KCl probe storage solution

• Never store the probe in RO, distilled or deionised water

• Avoid damaging the sensitive glass probe tip

Correct cleaning, calibration and storage can significantly improve the consistency and usable life of your pH probe.

What's Included?

The Bluelab pH PenPlus package includes:

• 1 x Bluelab pH PenPlus

• 1 x Replaceable Bluelab pH ProbePlus

• 1 x pH 7.0 Calibration Solution Sachet

• 1 x pH 4.0 Calibration Solution Sachet

• 1 x KCl Storage Solution

• Battery

• Getting-started documentation

If you're looking for a reliable waterproof digital pH meter for hydroponics, the Bluelab pH PenPlus combines accuracy, durability and long-term serviceability in one convenient handheld device.

The biggest advantage is simple: when the probe wears out, replace the probe—not the whole meter.

Combined with its IP68 waterproof construction, double-junction probe, pH and temperature measurement, backlit screen and calibration reminder, the Bluelab pH PenPlus is an excellent choice for serious home growers and professional hydroponic environments.

Monitor your nutrient solution with confidence and keep one of the most important growing parameters under control with the Bluelab pH PenPlus.