Bluelab EC Pen - Temperature Compensated Digital EC Tester
Best for: growers who want a fast, single-purpose conductivity check on their nutrient solution without carrying a full combo meter.
Our thoughts
If pH isn't your worry and you just want to know your feed strength is on point, this is the pen for the job. It's simple, it's quick, and Bluelab's build quality means it'll survive being dunked in a reservoir daily for years rather than dying after one season.
The Bluelab EC Pen is a handheld digital tester dedicated to conductivity, giving you a reading in EC, CF, PPM 500 or PPM 700 with automatic temperature compensation so the number stays accurate whether your reservoir is warm or cold. It's waterproof, runs on standard batteries, and auto-calibrates against a single EC standard solution, making it a quick single-point check rather than the more involved two-point pH calibration process.
How it compares
It's a focused, single-parameter alternative to Bluelab's own combo devices and to other brands' EC/TDS testers.
- Versus the Bluelab Combo Meter or One Pen, the EC Pen is cheaper and simpler because it only measures conductivity and temperature, not pH.
- Versus Hanna Instruments' DiST-series EC/TDS testers or a Milwaukee MW302, Bluelab's pens are built specifically with hydroponic growers in mind and are widely used across UK grow shops as the go-to for reservoir checks.
- Versus a generic supermarket TDS pen, the EC Pen offers proper temperature compensation and the option to read in EC or CF, not just PPM, which matters if you're following a nutrient brand's own feed chart.
If pH isn't your immediate concern, this covers the EC side of feeding accurately without paying for functions you don't need.
Usage guidance
Straightforward to use once calibrated, and calibration itself only takes a minute.
Calibration
Calibrate against Bluelab's 2.77 EC standard solution before first use, then periodically to keep readings accurate.
Testing your reservoir
Dip the probe into your nutrient solution, wait for the reading to stabilise, and take your EC/CF/PPM figure straight off the display.
Care between uses
Rinse the probe after testing strong nutrient solutions and store the cap with a drop of water or Bluelab storage solution to stop the sensor drying out.
Technical specifications
- Parameter measured: conductivity (EC/CF/PPM 500/PPM 700) with temperature compensation
- Housing: waterproof, handheld pen design
- Calibration: single-point, using 2.77 EC standard solution
- Display: digital LCD
- Auto-off: yes
- Typical use: hydroponic reservoirs, coco and soil run-off feed checks
Who this is for
- Growers who already have a separate pH pen and just need a reliable EC check
- Anyone following a strict feed chart in EC, CF or PPM who wants a consistent number they can trust
- Hydro, coco and soil growers checking reservoir or run-off strength regularly
- Growers upgrading from an unreliable budget TDS pen
A good fit for anyone who wants one job - accurate EC readings - done well, without paying for pH measurement they won't use.
Our take
This is Bluelab doing what it does best: a simple, durable, accurate single-purpose tool that takes the guesswork out of feed strength. It won't tell you your pH, but for that job alone it's hard to beat at this price point.
Worth picking up if you want straightforward, reliable EC readings without paying for a full combo meter you don't need.
