Extech ExStik II PH100
#5 in Pen testersFull review
A pen with a flat electrode for checking cheese, meat, paper or wet surfaces as well as liquids.
Amazon $129.50$129.50
The Extech ExStik II PH100 is the better ph meter overall, rated 3.6 to 3.0. The Extech ExStik II PH100 leads on accuracy and features. The Bluelab pH PenPlus costs $14.50 less ($115 vs $129.50).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Bluelab pH PenPlus
#12 in Pen testersFull review
The Bluelab pH Pen with a replaceable probe and a longer warranty, for growers who want a pen that lasts. Pick the Apera PH60 if you need finer resolution.
Amazon $115$115
Which should you buy?
- Choose the Extech ExStik II PH100 for accuracy (±0.01 pH vs ±0.1 pH) and features (replaceable probe, automatic temperature compensation, waterproof, stores readings vs replaceable probe, automatic temperature compensation, waterproof (IP68)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every pen testers ph meter; a clear win is highlighted. How we rank explains each one.
| Factor weight | Extech ExStik II PH100 | Bluelab pH PenPlus |
|---|---|---|
| Overall rating | 3.6/5 | 3.0/5 |
| Accuracy 30% | 81 ±0.01 pH | 19 ±0.1 pH |
| Calibration 15% | 50 calibration points not published (neutral score used) | 50 2-point calibration |
| Features 20% | 90 replaceable probe, automatic temperature compensation, waterproof, stores readings | 80 replaceable probe, automatic temperature compensation, waterproof (IP68) |
| Extra readings 10% | 0 pH and temperature only | 0 pH and temperature only |
| Price 15% | 67 $129.50 | 72 $115 |
| Warranty 10% | 0 warranty not published, scored as none | 25 2-year meter warranty |
Specifications
| Extech ExStik II PH100 | Bluelab pH PenPlus | |
|---|---|---|
| pH measurement | ||
| Accuracy | ±0.01 pH | ±0.1 pH |
| Resolution | 0.01 pH | 0.1 pH |
| Range | 0 to 14 pH | 0 to 14 pH |
| Calibration | - | 2-point |
| Temperature compensation | Yes | Yes |
| Other readings | ||
| Conductivity (EC/TDS) | No | No |
| ORP | No | No |
| Salinity | No | No |
| Build | ||
| Replaceable probe | Yes | Yes |
| Waterproof rating | Waterproof | IP68 |
| Stored readings | 15 readings | - |
| Meter warranty | - | 2 years |
| Probe warranty | - | 6 months |