Bluelab Combo Meter - One Handheld Pen for pH, EC and Temperature
Best for: hobby and mid-level growers who want pH, conductivity and temperature readings from a single handheld meter instead of juggling three separate pens.
Our thoughts
This is the meter a lot of growers graduate to once they're tired of carrying a pH pen in one pocket and an EC pen in the other. It's not cheap, but it earns its keep by cutting your daily reservoir check down to one dip instead of two or three. Some growers nickname it the "Cadillac of meters" for a reason - it's built to be dropped in a tent, dunked in a tank and still give you a straight answer.
The Bluelab Combo Meter is a 3-in-1 handheld tester that reads pH, conductivity (selectable in EC, CF, PPM 500 or PPM 700) and solution temperature from a single probe housing, wired to a compact handheld display unit. The probe combines a double-junction pH sensor with a conductivity ring and a built-in thermistor, so one dip in your reservoir gives you every number that matters for feed strength and pH balance. It's waterproof and buoyant, runs off two AAA batteries, and auto-calibration prompts help stop drift creeping into your readings unnoticed.
How it compares
It sits above single-parameter pens and below Bluelab's own wireless Guardian Connect monitor in the range.
- Versus buying a separate Bluelab pH Pen and EC Pen, the Combo Meter costs more up front but replaces two dips with one and removes the risk of two devices disagreeing with each other.
- Versus combo testers from Hanna Instruments or Milwaukee, Bluelab's reputation in UK grow rooms specifically is built on the double-junction probe holding up better against nutrient fouling than cheaper single-junction electrodes.
- Versus Bluelab's wireless Guardian Connect, the Combo Meter is a manual handheld check rather than continuous remote monitoring - fine for growers happy to test once or twice a day rather than track it on a phone.
If you want one accurate reading source rather than three separate pens that can drift out of sync, this is the sensible buy.
Usage guidance
Get it calibrated properly and it'll stay accurate for months between services.
Calibration
Use Bluelab pH 4.0 and 7.0 calibration solution for a standard two-point pH calibration, and Bluelab 2.77 EC solution to calibrate conductivity. Do this before first use and then periodically through a grow.
Daily testing
Dip the probe into your reservoir or run-off, give it a few seconds to stabilise, and read pH, EC and temperature off the display in one go.
Storage
Keep the probe cap topped up with Bluelab probe storage solution between uses rather than letting it dry out - this is what actually kills probes early, not general wear.
Cleaning
Rinse the probe after use in nutrient-rich water and give it an occasional clean with Bluelab's probe cleaning solution to stop mineral scale building up on the conductivity ring.
Technical specifications
- Parameters measured: pH, conductivity (EC/CF/PPM 500/PPM 700), temperature
- Probe type: double-junction pH sensor + conductivity ring + thermistor, single housing
- Power: 2 x AAA batteries
- Housing: waterproof, buoyant handheld unit
- Calibration: 2-point pH (4.0/7.0), 1-point EC (2.77) - solutions sold separately
- Display: digital LCD, simultaneous pH/EC/temperature readout
- Auto-off: yes, to preserve battery life
- Typical use: hydroponic reservoirs, coco and soil run-off testing
Who this is for
- Growers currently running separate pH and EC pens who want to consolidate into one device
- Hobby to mid-level hydroponic, coco or soil growers who test feed water regularly
- Anyone who wants lab-grade consistency without stepping up to a full wireless monitoring system
- Growers who've had cheaper meters drift or die early and want something built to last in a grow room environment
Best suited to growers who test daily and want one reliable number they can trust, rather than cross-checking two separate pens.
Our take
The Combo Meter earns its price by doing the job of two or three pens properly, in a housing built to survive actual grow room use - splashes, drops and all. It's an investment piece rather than an impulse buy, but it's the kind of tool that pays for itself in fewer feeding mistakes.
If you're ready to stop guessing and want one trustworthy readout for pH, EC and temperature, this is the obvious step up. Does exactly what it should, day in, day out.
