# Bluelab pH Pen vs Extech PH100 ExStik II Waterproof pH Meter: specs and price compared

A sourced, side-by-side comparison of the Bluelab pH Pen (Bluelab) and Extech PH100 ExStik II Waterproof pH Meter (Extech Instruments) among ph meters. Bluelab pH Pen is the cheaper of the two at $99.

## Side by side

| Spec | Bluelab pH Pen | Extech PH100 ExStik II Waterproof pH Meter |
| --- | --- | --- |
| US price | $99 | $124 |
| Brand | Bluelab | Extech Instruments |
| 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 |

## Key differences

- 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

## Sources

- Bluelab pH Pen: https://www.bluelab.com/products/bluelab-ph-pen (bluelab.com, verified 2026-08-12)
- Extech PH100 ExStik II Waterproof pH Meter: https://www.extech.com/products/PH100 (extech.com, verified 2026-08-12)

Canonical: https://frontdeskreview.com/gear/ph-meters/bluelab-ph-pen-vs-extech-ph100/
Cite: Per The Front Desk Review, Bluelab pH Pen ($99) vs Extech PH100 ExStik II Waterproof pH Meter ($124) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/ph-meters/bluelab-ph-pen-vs-extech-ph100/
License: CC BY 4.0.