# Bluelab pH Pen vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe: specs and price compared

A sourced, side-by-side comparison of the Bluelab pH Pen (Bluelab) and Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe (Atlas Scientific) among ph meters. Bluelab pH Pen is the cheaper of the two at $99.

## Side by side

| Spec | Bluelab pH Pen | Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe |
| --- | --- | --- |
| US price | $99 | $174.99 |
| Brand | Bluelab | Atlas Scientific |
| Ph range | 0.0 to 14.0 | 0 to 14 pH |
| Resolution ph | 0.1 | 0.001 pH |
| Accuracy ph | ±0.1 at 25°C/77°F | ±0.002 pH (probe reading accuracy) |
| Calibration points | Two-point (pH 7.0 and pH 4.0 solutions), with a built-in 30-day calibration reminder | Up to 3-point; kit includes 6x 20ml calibration solution pouches (2x pH 4, 2x pH 7, 2x pH 10) |
| Atc | Yes, fully temperature compensated | — |
| Electrode type | Double-junction pH probe | Double-junction Ag/AgCl Gen 3 Lab Grade pH probe (BNC connection to EZO pH circuit board) |
| Waterproof rating | Waterproof; floats in any solution | — |
| Battery type | 1 x AAA alkaline | None — EZO circuit is powered by the host carrier/development board, no internal battery |

## Key differences

- Ph range: Bluelab pH Pen 0.0 to 14.0 vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe 0 to 14 pH
- Resolution ph: Bluelab pH Pen 0.1 vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe 0.001 pH
- Accuracy ph: Bluelab pH Pen ±0.1 at 25°C/77°F vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe ±0.002 pH (probe reading accuracy)
- Calibration points: Bluelab pH Pen Two-point (pH 7.0 and pH 4.0 solutions), with a built-in 30-day calibration reminder vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe Up to 3-point; kit includes 6x 20ml calibration solution pouches (2x pH 4, 2x pH 7, 2x pH 10)
- Electrode type: Bluelab pH Pen Double-junction pH probe vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe Double-junction Ag/AgCl Gen 3 Lab Grade pH probe (BNC connection to EZO pH circuit board)
- Battery type: Bluelab pH Pen 1 x AAA alkaline vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe None — EZO circuit is powered by the host carrier/development board, no internal battery

## Sources

- Bluelab pH Pen: https://www.bluelab.com/products/bluelab-ph-pen (bluelab.com, verified 2026-08-12)
- Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe: https://atlas-scientific.com/kits/ph-kit/ (atlas-scientific.com, verified 2026-08-12)

Canonical: https://frontdeskreview.com/gear/ph-meters/bluelab-ph-pen-vs-atlas-scientific-ph-kit/
Cite: Per The Front Desk Review, Bluelab pH Pen ($99) vs Atlas Scientific pH Kit (KIT-101P) — EZO pH Circuit + Gen 3 Lab Grade Probe ($174.99) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/ph-meters/bluelab-ph-pen-vs-atlas-scientific-ph-kit/
License: CC BY 4.0.