Question 1

What does the Apera PH60 measure?

Accepted Answer

The Apera PH60 (AI311) measures pH (0-14, ±0.01 accuracy), millivolts/mV (-1999 to +1999 mV), ORP/Oxidation-Reduction Potential (when the ORP60-E probe is installed), and temperature (32-122°F / 0-50°C, ±0.9°F accuracy) with automatic temperature compensation (ATC). It uses a replaceable combination pH probe that includes a built-in temperature sensor for ATC.

Question 2

What is the difference between the Apera PH60 and the Apera PC60?

Accepted Answer

The PH60 is a dedicated pH/mV/ORP/temperature meter. The PC60 is a 5-in-1 multiparameter meter that adds electrical conductivity (EC), TDS, and salinity to the pH and temperature measurement. The PH60 at $79.76 is the right choice if pH monitoring is the primary need. The PC60 at $147.58 is the right choice if you also need EC, TDS, and salinity from the same instrument. Both use replaceable probes and share the same IP67 rating, calibration approach, and 3-button interface.

Question 3

What is ORP and how does the PH60 measure it?

Accepted Answer

ORP (Oxidation-Reduction Potential) measures the ability of a liquid to act as an oxidizing or reducing agent, expressed in millivolts (mV). A positive ORP indicates an oxidizing environment; a negative ORP indicates a reducing environment. In water treatment, ORP is used to assess disinfection effectiveness — chlorinated water typically shows ORP above +650 mV at effective disinfection levels. The PH60 measures ORP in mV mode when the ORP60-E probe (sold separately, SKU AI1207) is installed. The standard PH60-E pH probe does not measure ORP.

Question 4

Why does the Apera PH60 LCD turn green or red?

Accepted Answer

The 3-color LCD on the PH60 provides instant visual pH status. Blue: the pH reading is neutral (6.5-7.5 pH range). Green: the pH reading is in a normal water quality range (above 7.5, slightly alkaline). Red: the pH reading is outside the safe range (below 6.5, acidic conditions that may indicate water quality issues). In calibration mode, the display turns green to indicate active calibration mode regardless of the pH value. This color system allows at-a-glance status assessment without reading the numeric value.

Question 5

How long does the Apera PH60 probe last and when should it be replaced?

Accepted Answer

The PH60-E probe typically lasts 1-2 years with proper care, depending on use frequency and sample types. Replace when: readings drift continuously and will not stabilize despite proper KCl soaking and cleaning; the probe reads approximately 7.00 pH in all solutions regardless of actual pH; calibration fails repeatedly with fresh, quality buffers; or readings jump erratically and refuse to settle. The probe is user-replaceable — unscrew the probe ring counterclockwise, unplug old probe, plug in new probe (checking alignment), screw ring clockwise, soak in KCl 5-15 minutes, and recalibrate before use.

Feature	PH60 (AI311) — $79.76	PC60 (AI316) — $147.58
pH measurement	✓	✓
Temperature / ATC	✓	✓
mV / ORP (with ORP probe)	✓ — core feature	✗
Conductivity (EC)	✗	✓
TDS	✗	✓
Salinity	✗	✓
Best for	pH-focused monitoring; pool/spa ORP; wastewater disinfection verification	Multi-parameter: RO performance, cooling towers, hydroponics, aquaculture

Button	Short Press (<2 sec)	Long Press (>2 sec)
MEAS	Power on; toggle backlight	Enter Parameter Settings (P1–P7) — must be powered OFF; hold to exit settings
MODE	Switch measurement mode: pH → mV (ORP) → Temp → pH	Power off; advance through parameters in settings mode
CAL	Confirm calibration point; release Auto-Hold; select/change in settings	Enter calibration mode (screen turns GREEN)

Setting	Function	Options	Default
P1	pH buffer standard series	USA (4.00/7.00/10.01) or NIST (4.00/6.86/9.18)	USA
P2	Auto shut-off timer	5 / 10 / 30 min / Off	10 min
P3	Temperature unit	°C or °F	°C
P4	Auto-Hold function	On or Off	Off — enable for unattended field monitoring
P5	pH reading alarm — low threshold	0.0–14.0 pH (alarm when pH falls below set value)	Off
P6	pH reading alarm — high threshold	0.0–14.0 pH (alarm when pH rises above set value)	Off
P7	Factory reset	No / Yes	No — Yes clears all calibration data
Access settings: power OFF, then long press MEAS. Short press MODE to cycle P1→P7. Short press CAL to select. Short press MODE to change value. Short press CAL to confirm. Long press MEAS to exit.

Signs of a Failing Probe	What It Means
Reading always slowly drifts, won’t stabilize	Glass membrane dehydrated or reference junction clogged. Soak in KCl 30 min. If persistent, replace probe.
Reads approximately 7.00 in all samples	Broken or dead glass membrane. Replace probe.
Similar readings in very different solutions	Loss of electrode slope response. Replace probe.
Calibration fails repeatedly with fresh buffers	Probe response degraded. Deep clean, KCl soak 1 hour, retry. Replace if still failing.
Erratic, randomly jumping readings	Loose probe connection or damaged cable. Check probe connection; replace probe if connection is secure.

Symptom	Cause	Resolution
pH reading won’t stabilize	Probe stored dry or in pure water; glass membrane dehydrated	Soak in 3M KCl 15–30 min; recalibrate
Calibration not recognized / fails	Wrong buffer series in P1; contaminated buffers; probe needs cleaning	Check P1 (USA vs NIST); replace buffers; deep clean + 1 hr KCl soak; recalibrate
ORP reads erratically	ORP probe needs conditioning; sample has very low oxidant level	Allow longer equilibration time (2–5 min); verify ORP60-E probe is installed (not PH60-E)
Auto-Hold locks too fast or won’t lock	P4 setting; stability threshold	Check P4 is On; if locking prematurely, allow full equilibration before placing in sample
Display shows “Err”	Probe not connected; probe outside measurement range	Check probe ring is fully tightened; verify sample is within 0–14 pH / 0–50°C range
Short battery life	Backlight on; auto-shutoff disabled	Toggle backlight; verify P2 auto-shutoff is not set to Off

Apera Instruments PH60 (AI311) Review & Complete Reference (2026)

PH60 vs PC60 — Which Apera Tester Do You Need?

3-Color LCD — Instant Visual Status

Keypad Reference

pH Calibration — Complete Procedure

Power on — rinse probe in pure water — shake off excess

Dip into pH 7.00 buffer first — stir briefly — hold still

Long press CAL — screen turns GREEN — wait for smiley face ☺ to appear AND stay

Short press CAL to confirm — M icon confirms 1-point complete

ORP (mV) Measurement — Disinfection Monitoring

ORP Measurement Procedure

Install ORP60-E probe — short press MODE to switch to mV mode

Rinse probe in distilled water — shake off excess

Dip into sample — stir briefly — wait for smiley face stability icon

Auto-Hold Feature

Parameter Settings (P1–P7)

Probe Care & Storage

Troubleshooting

Related Apera & Hach Instrument References