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Bluelab
Bluelab pH Pen
$99Cheaper
Best Ph Meters · head-to-head
Bluelab pH Pen vs Extech PH100 ExStik II Waterproof pH Meter
A sourced, side-by-side comparison. Bluelab pH Pen is cheaper at $99. Every spec and price links to its source.
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Extech Instruments
Extech PH100 ExStik II Waterproof pH Meter
$124
Which is better: the Bluelab pH Pen or Extech PH100 ExStik II Waterproof pH Meter?
On the specs we track, they're closely matched. The Bluelab pH Pen is the cheaper at $99.
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Bluelab pH Pen | Extech PH100 ExStik II Waterproof pH Meter |
|---|---|---|
| US price | $99 | $124 |
| Brand | Bluelab | Extech Instruments |
| Released | — | — |
| Ph range | 0.0 to 14.0 | 0.00 to 14.00 pH |
| Resolution ph | 0.1 | 0.01 pH |
| Accuracy ph | ±0.1 at 25°C/77°F | ±0.01 pH |
| Calibration points | Two-point (pH 7.0 and pH 4.0 solutions), with a built-in 30-day calibration reminder | — |
| Atc | Yes, fully temperature compensated | Yes, automatic |
| Electrode type | Double-junction pH probe | Flat-surface electrode (rated for liquids, semi-solids, and solids) |
| Waterproof rating | Waterproof; floats in any solution | IP57 |
| Battery type | 1 x AAA alkaline | 4 x CR2032 3V button cell |
Sources — Bluelab pH Pen: bluelab.com (verified 2026-08-12). Extech PH100 ExStik II Waterproof pH Meter: extech.com (verified 2026-08-12).
What's the difference between the Bluelab pH Pen and Extech PH100 ExStik II Waterproof pH Meter?
Where the two actually differ on the specs we track (7 of 8). Matching specs are omitted.
- Ph range: Bluelab pH Pen 0.0 to 14.0 vs Extech PH100 ExStik II Waterproof pH Meter 0.00 to 14.00 pH
- Resolution ph: Bluelab pH Pen 0.1 vs Extech PH100 ExStik II Waterproof pH Meter 0.01 pH
- Accuracy ph: Bluelab pH Pen ±0.1 at 25°C/77°F vs Extech PH100 ExStik II Waterproof pH Meter ±0.01 pH
- Atc: Bluelab pH Pen Yes, fully temperature compensated vs Extech PH100 ExStik II Waterproof pH Meter Yes, automatic
- Electrode type: Bluelab pH Pen Double-junction pH probe vs Extech PH100 ExStik II Waterproof pH Meter Flat-surface electrode (rated for liquids, semi-solids, and solids)
- Waterproof rating: Bluelab pH Pen Waterproof; floats in any solution vs Extech PH100 ExStik II Waterproof pH Meter IP57
- Battery type: Bluelab pH Pen 1 x AAA alkaline vs Extech PH100 ExStik II Waterproof pH Meter 4 x CR2032 3V button cell