Bluelab Conductivity Pen

Bluelab Conductivity Pen — Compact EC & Temperature Meter for Hydroponic Nutrient Monitoring

The Bluelab® Conductivity Pen is the go-to handheld EC meter for growers who need a fast, accurate, and portable way to check nutrient concentration and temperature in their hydroponic solution. Compact and fully waterproof, the Conductivity Pen delivers quick, reliable readings with automatic temperature compensation (ATC) — so your EC readings are always accurate regardless of solution temperature.

Selectable units for both conductivity (EC, PPM ×500, PPM ×700) and temperature (°C, °F) make the pen compatible with any nutrient program or growing guide. The backlit LCD display is easy to read in low-light grow room conditions, and practical features like a hold reading function, auto-off, and low battery indicator make it a reliable everyday tool. Calibration is optional — the pen is factory-calibrated and ready to use out of the box, but can be calibrated against a reference solution for maximum accuracy. Runs on a single AAA battery (included).

Specifications

• Measures: EC, PPM ×500, PPM ×700, temperature (°C/°F)
• Range: 0.0–10.0 EC / 0–5,000 PPM (×500) / 0–7,000 PPM (×700) / 0–50°C (32–122°F)
• Resolution: 0.1 EC / 10 PPM / 1°C (1°F)
• Accuracy @ 25°C: ±0.1 EC (@ 2.77 EC) / ±50 PPM (×500) / ±70 PPM (×700) / ±1°C (±2°F)
• Automatic temperature compensation (ATC)
• Fully waterproof
• Battery: 1 × AAA alkaline (included)

Frequently Asked Questions

What does the Bluelab Conductivity Pen measure and why does it matter for hydroponics?

The Bluelab Conductivity Pen measures electrical conductivity (EC) and temperature of your nutrient solution. EC is a direct indicator of the total dissolved nutrient concentration in your reservoir — the higher the EC, the more nutrients are present. Monitoring EC is essential in hydroponics because both under-feeding (low EC) and over-feeding (high EC) can stress plants and reduce yields. The integrated temperature sensor enables automatic temperature compensation (ATC), ensuring EC readings are accurate regardless of solution temperature, which can vary significantly between seasons or grow environments.

Does the Bluelab Conductivity Pen need to be calibrated?

Calibration is optional. The Conductivity Pen is factory-calibrated and ready to use out of the box. For growers who want maximum accuracy, the pen can be calibrated against a known reference solution such as the Bluelab 2.77EC Conductivity Solution. A successful calibration indicator confirms when calibration has been completed correctly. For most hobby and commercial growers, the factory calibration provides sufficient accuracy for routine nutrient monitoring.

What conductivity units does the Bluelab Conductivity Pen support?

The pen supports three selectable conductivity units: EC (electrical conductivity in mS/cm), PPM ×500 (parts per million using a 500 conversion factor), and PPM ×700 (parts per million using a 700 conversion factor). Temperature can be displayed in °C or °F. This flexibility makes the pen compatible with any nutrient program or growing guide, regardless of which measurement convention it uses.

Is the Bluelab Conductivity Pen waterproof?

Yes. The Bluelab Conductivity Pen is fully waterproof, making it suitable for use in wet grow room environments, greenhouses, and outdoor settings. The waterproof construction protects the electronics from accidental submersion, splashes, and the humid conditions typical of hydroponic operations. The hold reading function also allows you to lock a reading on the display before removing the pen from the solution, making it easy to record measurements in challenging conditions.

Where can I buy the Bluelab Conductivity Pen?

The Bluelab Conductivity Pen is available through Seres Ag, a professional hydroponic and CEA equipment supplier serving growers across the United States. Purchase directly at seresag.com. Seres Ag offers expert product support, competitive wholesale and retail pricing, and US-wide shipping. For bulk or wholesale inquiries, contact the Seres Ag team through the website.