Apera PH20
#9 in Pen testersFull review
A cheap, waterproof pen for pools, aquariums and drinking water. Pick it when 0.1 pH is close enough.
Amazon $56.65$56.65
±0.1 pH3-pointNone
3.0/5
A low-cost pen with a replaceable electrode, for pools, gardens and aquariums. The Apera PH60 is more accurate for a little more.
- ±0.1 pHAccuracy
- 2-pointCalibration
- IP65Waterproof
- YesReplaceable probe
Check price at Amazon$77.90
Price checked November 8, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Replaceable double-junction electrode at an entry price
- Wide -2 to 16 pH range
Cons
- Reads to 0.1 pH only
- Only about 300 hours per set of batteries
The Milwaukee waterproof testers family
Every Milwaukee waterproof testers model we rank, smallest first. Ratings compare each against its own type.
| Model | Accuracy | Rating | Price |
|---|---|---|---|
| Milwaukee pH55 Pro (this one) | ±0.1 pH | 3.0/5 | $77.90 |
| Milwaukee pH58 Max pH/ORP | ±0.05 pH | 3.2/5 | $219.65 |
How it scores
The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its type. How we rank explains each one.
Specifications
| Model number | pH55 |
|---|---|
| pH measurement | |
| Accuracy | ±0.1 pH |
| Resolution | 0.1 pH |
| Range | -2 to 16 pH |
| Calibration | 2-point |
| Temperature compensation | Yes |
| Other readings | |
| Conductivity (EC/TDS) | No |
| ORP | No |
| Salinity | No |
| Build | |
| Replaceable probe | Yes |
| Waterproof rating | IP65 |
| Battery life | 300 hours |
| Weight | 99 g |
| Meter warranty | 2 years |
| Probe warranty | 6 months |
Alternatives in this type
Hanna pHep 5 HI98128
#10 in Pen testersFull review
A well-made pocket tester from a lab brand, for anyone who already uses Hanna buffers and electrodes. The Apera PH60 does more for less.
Amazon $179.99$179.99
±0.05 pH3-pointNone
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
±0.1 pH2-pointNone
Compare
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