Featured product
Bluelab Truncheon EC Meter
Bluelab
Best for: Daily reservoir checks in DWC and drip systems
Type
EC / CF / PPM stick meter
Calibration
Not required on classic Truncheon
Use case
Reservoir strength checks
Pair with
Calibrated pH pen
Pros
- + Durable, wet-area friendly design
- + No routine calibration on classic Truncheon models
- + Fast checks in reservoirs and buckets
- + Trusted in commercial and serious home rooms
Cons
- − Higher upfront cost than pocket pens
- − Bulkier to store than a tiny TDS stick
- − You must still know which PPM factor you are reading
How we evaluate this category
We prioritize repeatability in nutrient solution, durability around splash and humidity, and clarity of EC vs PPM display so growers do not chase the wrong scale.
We do not accept payment for rankings.
Best TDS meter for hydroponics — shortlist
If you want one answer: buy a durable EC/TDS stick you will actually use every reservoir change. Cheap pens teach the habit; workhorse meters keep readings trustworthy in wet rooms for years.
Our editorial pick for most serious home growers is the Bluelab Truncheon class: dip, read EC/CF/PPM, rinse. If budget is tight, a reputable pocket EC/TDS pen still beats guessing — just learn your 500 vs 700 scale.
EC is the real measurement; PPM is a translation
Electrical conductivity measures ionic strength. PPM displays estimate solids using a factor (often 500 or 700). Two honest meters can disagree on PPM while agreeing on EC.
Log EC in mS/cm when you can. When a chart only lists PPM, convert with a known scale — our PPM ↔ EC tool exists for that exact argument.
Bluelab Truncheon review notes
Grow rooms are wet, humid, and rough on electronics. A sealed stick you dip and read beats a fragile pen you fear dropping in a tote. Classic Truncheon meters are built around that workflow and skip the calibration choreography many pocket EC pens demand.
That convenience is worth money if you change reservoirs weekly and measure every top-off. Confirm whether your display uses a 700-factor PPM reading, and prefer the EC number when sharing recipes online.
How to measure correctly
Mix nutrients thoroughly, wait a minute, measure mid-depth away from concentrated pockets. Rinse the probe after dirty tanks. Do not interpret a rising EC during volume loss as “plants need more fertilizer” without checking whether water simply evaporated.
Alternatives
Combo pH/TDS pens: Convenient, but pH side still needs calibration discipline.
Inline EC monitors: Great for automation later; not required for first grows.
Verdict
Pair a trusted EC meter with a calibrated pH pen and you have the core lab kit. The Truncheon earns its keep if you measure often and hate fiddly calibration rituals.
Frequently asked questions
What is the best TDS meter for hydroponics?
For frequent wet-room use, a durable Bluelab Truncheon-style EC/TDS stick is our top pick. A quality pocket pen works for learning if you know your PPM scale and rinse after every dip.
What is the best EC meter for hydroponics?
Same shortlist — buy a meter that shows EC (mS/cm) clearly. EC is the shared language; PPM is a conversion. Pair it with a calibrated pH pen.
Do I need both pH and EC meters?
Yes. EC tells strength; pH tells availability. One without the other causes misdiagnosis.
Is Bluelab 700 or 500 scale?
Many Bluelab PPM displays use a 700 factor (and also show EC/CF). Always confirm on your exact model and prefer EC for sharing recipes.
Can a cheap TDS pen work?
For learning, yes. For long-term accuracy in wet rooms, durable EC meters reduce frustration.