What does the Apera PC60 measure?

The Apera PC60 (AI316) measures five parameters simultaneously from a single probe immersion: pH (0-14, ±0.01 resolution), Electrical Conductivity or EC (0-20 mS/cm, ±1% full scale), Total Dissolved Solids or TDS (0-10 ppt, ±1% full scale), Salinity (0-10 ppt, ±1% full scale), and Temperature (32-122°F / 0-50°C, ±0.9°F/±0.5°C). All five parameters are measured by the single replaceable PC60-E combination probe housing both a pH glass membrane and a platinum black conductivity sensor.

How do you calibrate the Apera PC60?

The PC60 supports separate pH and conductivity calibration using 1, 2, or 3 calibration points each. For pH: power on, dip probe in pH 7.00 buffer first, long-press CAL (screen turns green), wait for the smiley-face stability icon, short-press CAL to confirm. Add pH 4.00 or 10.01 for 2-point, and all three for full 3-point calibration. For conductivity: switch to Cond mode, long-press CAL, dip in 1413 µS standard, wait for stability, short-press CAL. One conductivity calibration simultaneously calibrates EC, TDS, salinity, and resistivity. Always calibrate before use and after extended storage.

What is the Apera PC60 probe and how often should it be replaced?

The PC60-E is a combination probe housing both a pH glass membrane electrode and a platinum black conductivity sensor in one replaceable assembly. It is a consumable with a typical lifespan of 1-2 years depending on use frequency and sample characteristics. Replace when: pH readings stabilize slowly despite proper soaking and cleaning, calibration is difficult or produces large offset values, or readings are inconsistent despite proper technique. The probe is user-replaceable — unscrew the probe ring counterclockwise, unplug old probe, plug in new probe aligned correctly, screw ring clockwise, soak in KCl solution 5-15 minutes, re-calibrate.

What is the difference between the Apera PC60 and the Hach DR900?

The Apera PC60 and Hach DR900 are complementary instruments serving different measurement principles. The PC60 is an electrochemical meter measuring pH, EC, TDS, salinity, and temperature through direct probe contact with the water sample. The DR900 is a colorimetric instrument measuring parameters like chlorine, iron, phosphate, and COD by measuring light absorbance of chemically treated water samples — parameters the PC60 cannot measure. A complete water quality monitoring program typically needs both: the PC60 for electrochemical parameters and the DR900 (or DR300 series) for colorimetric parameters.

Why should the Apera PC60 probe be stored in KCl solution and not pure water?

The pH glass membrane electrode requires a moist ionic environment to maintain its ion exchange capability and reference junction stability. Storing the probe in pure water (distilled, deionized, or RO water) rapidly dilutes the internal reference electrolyte, destabilizes the glass membrane, and degrades pH measurement accuracy — sometimes permanently. The 3M KCl (potassium chloride) soaking solution maintains the correct ionic concentration around the reference junction and glass membrane. Always store the probe tip submerged in 3M KCl solution, either in the probe cap filled with KCl or in a dedicated storage bottle. If the probe was stored dry or in pure water, soak in KCl for at least 15 minutes before calibrating.

What applications is the Apera PC60 best suited for?

The PC60 is well suited for: water treatment process monitoring (softener influent/effluent TDS and conductivity, RO system performance via TDS rejection ratio), cooling tower and boiler water chemistry checks, pool and spa water quality (pH and conductivity), hydroponics and aquaculture (pH and EC monitoring critical for nutrient solution and fish health), environmental field monitoring, laboratory quality control and sample screening, and food and beverage process water. At $147 with 300+ monthly purchases and an Overall Pick badge, it fills the multiparameter field meter role at a price point well below dedicated laboratory instruments.

Product Review & Technical Reference — Apera Instruments

Apera Instruments PC60 (AI316) Review & Complete Reference (2026): 5-in-1 pH/EC/TDS/Salinity/Temp

Source: Official PC60 User Manual v8.3 (Apera Instruments, LLC) • Amazon Overall Pick • 300+ bought/month • 4.5 stars (1,200+ reviews)

AI316 • IP67 Waterproof • Replaceable PC60-E Probe • ISO 9001:2015 • RoHS • CE • $147.58

Apera Instruments AI316 PC60 5-in-1 multiparameter tester kit with carrying case, calibration solutions, and accessories

Apera PC60 applications: education, water treatment, pools and spas, aquaculture, horticulture

Apera Instruments AI316 PC60 5-in-1 Tester Kit — $147.58

pH • EC • TDS • Salinity • Temp • IP67 • Replaceable probe • Amazon Overall Pick • 300+ bought/month. Ships with carrying case, 5 calibration solutions, and all accessories.

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Parameters

pH, EC, TDS, Salinity, Temp

pH Range

0–14 pH (±0.01 resolution)

EC Range

0–20 mS/cm (±1% FS)

TDS Range

0–10 ppt (±1% FS)

Salinity Range

0–10 ppt (±1% FS)

Temp Range

32–122°F / 0–50°C (±0.9°F)

Probe

PC60-E (replaceable)

IP Rating

IP67 Waterproof

Calibration

1–3 point (pH & EC separate)

Standards

ISO 9001:2015, RoHS, CE

Battery

4 × AAA

Price

$147.58 (kit)

Verdict: The Right Multiparameter Field Meter at This Price Point

The PC60 earns its Overall Pick badge and 300+ monthly sales because it solves a real problem: getting pH, EC, TDS, salinity, and temperature from a single probe immersion without carrying five separate instruments. At $147 with a replaceable probe (not a throw-away unit), ISO 9001 manufacturing, and a complete calibration kit included in the box, it sits in a defensible position against both cheaper disposable testers and laboratory-grade instruments that cost 5-10x more. The 3-button interface requires learning the short-press vs long-press distinction, and the KCl storage requirement catches new users off guard — but both are well-documented and the manual is clear. For water treatment process monitoring, cooling tower chemistry checks, RO performance verification, and hydroponics/aquaculture applications, the PC60 is the instrument to reach for before calling in a DR900 or benchtop meter.

What the PC60 Measures — Five Parameters, One Probe

The PC60-E is a combination probe housing two distinct sensing technologies in one assembly: a pH glass membrane electrode and a platinum black conductivity sensor. A single immersion gives you all five parameters simultaneously. This is the instrument’s core value proposition — and understanding how the five parameters relate to each other matters for interpreting the results.

Parameter	Range	Resolution	Accuracy	What It Tells You
pH	0–14	0.01 pH	±0.01 pH	Hydrogen ion activity; acidity/alkalinity. Critical for chemical reactions, disinfection efficacy, corrosion potential, and biological processes.
Conductivity (EC)	0–20 mS/cm	0.01–0.1 mS/cm	±1% FS	Ability of water to conduct electricity; directly proportional to dissolved ionic content. Higher EC = more dissolved salts/minerals.
TDS	0–10 ppt (mg/L)	1–10 mg/L	±1% FS	Total dissolved solids calculated from EC using a TDS factor (default 0.5). RO performance metric: compare influent vs effluent TDS for rejection ratio.
Salinity	0–10 ppt	0.01 ppt	±1% FS	Calculated from EC. Relevant for seawater applications, aquaculture, and desalination monitoring.
Temperature	32–122°F (0–50°C)	0.1°C	±0.5°C	Automatic temperature compensation (ATC) applied to pH and EC measurements. Displayed simultaneously with all other parameters.
TDS = EC × TDS factor (default 0.5, adjustable P3 setting 0.40–0.90). Salinity = derived from EC at measured temperature. All EC-derived parameters recalibrated simultaneously with one conductivity calibration.

Keypad Reference — Short Press vs Long Press

The PC60 has three physical buttons. The most important thing to understand before using the instrument is that every button has two functions: a short press (tap, under 2 seconds) and a long press (hold, over 2 seconds). These are distinct actions that trigger completely different responses.

Button	Short Press (<2 sec)	Long Press (>2 sec)
MEAS (top, with backlight icon)	Power on from off state; toggle backlight during measurement	Enter Parameter Settings mode (P1–P8) — only works when powered OFF; hold in Settings to exit
MODE (middle, with triangle)	Cycle through measurement parameters: pH → Cond → TDS → Sal → Temp → pH	Power off; in Settings: cycle to next parameter (P1→P2→…P8)
CAL (bottom, with check mark)	Confirm calibration point; in Settings: select/change parameter value	Enter calibration mode from measurement screen (screen turns GREEN)
The GREEN screen indicates calibration mode. The stability indicator (smiley face ☺) must appear and remain before confirming any calibration point.

First Use — Before You Take Any Measurement

Calibrate before every use session. The PC60 does not hold calibration indefinitely. pH electrodes drift with temperature changes, time, and sample exposure. Never take readings from an uncalibrated instrument and assume they are accurate.

Pull the battery insulation slip

The PC60 ships with a plastic slip in the battery compartment to prevent drain during transit. Pull it out before first power-on.

Remove probe cap — check for KCl solution

The probe cap ships with 3M KCl soaking solution inside. This is correct storage. If the probe arrived dry or was stored dry, soak the probe tip in 3M KCl solution for 15 minutes before proceeding.

Rinse probe in pure water — shake off excess

Use distilled, deionized, or RO water. Never wipe the pH glass membrane — shake off excess water only. Wiping generates static that interferes with pH measurement.

Perform pH calibration (Section below)

Start with the pH 7.00 buffer. Complete at minimum a 1-point calibration before any pH measurements.

Perform conductivity calibration (Section below)

One conductivity calibration covers EC, TDS, salinity, and resistivity simultaneously.

pH Calibration — Complete Procedure

pH calibration is the most critical maintenance step. The PC60 supports 1, 2, or 3-point calibration and automatically recognizes five standard pH buffer solutions in both USA and NIST series (pH 1.68, 4.00, 6.86, 7.00, 9.18, 10.01, 12.45).

Which Calibration Points to Use

Calibration Type	Buffers Used	Icons Confirmed	Best For
1-Point (minimum)	pH 7.00 only	M (Middle)	Samples expected near neutral pH; quick field checks
2-Point (recommended)	pH 7.00 + pH 4.00 or 10.01	M + L or M + H	Acidic samples (wastewater, pool water): use 4.00. Alkaline samples: use 10.01
3-Point (full range)	pH 7.00, 4.00, and 10.01	M + L + H	Samples with unknown or widely varying pH; compliance monitoring

Power on — short press MEAS

Confirm display is in pH mode. If not, short press MODE to cycle to pH.

Pour buffers into calibration vials — half volume

Use the labeled calibration vials included in the kit. Half-fill with the appropriate buffer solutions.

Always start with pH 7.00 buffer first

The PC60 requires the midpoint buffer first. Starting with pH 4.00 or 10.01 will cause calibration failure. Dip rinsed probe into pH 7.00 vial. Stir briefly, hold still.

Long press CAL — screen turns GREEN

Green screen confirms calibration mode is active.

Wait for smiley face ☺ to appear AND remain — then short press CAL

Do not press CAL while the reading is still changing. The smiley face must be stable. Premature confirmation locks in a drifting value and produces inaccurate results. M icon appears on screen = 1-point calibration complete.

For 2 or 3-point: rinse probe — dip in next buffer — wait for stability — short press CAL

Do NOT power off between calibration points — doing so resets the calibration and you must start over. L icon (pH 4.00) or H icon (pH 10.01) appears after each additional point.

Buffer care — never contaminate the bottles. pH 4.00 and 7.00 buffers in vials can be reused up to 10 times. pH 10.01 buffer can only be reused up to 5 times (degrades from CO₂ absorption). Never pour used calibration buffer back into the original bottles — this contaminates the entire stock and invalidates future calibrations.

Conductivity Calibration — Covers EC, TDS, Salinity, and Resistivity

One conductivity calibration simultaneously calibrates all four derived parameters. The PC60 accepts up to 3-point conductivity calibration using three standard solutions.

Calibration Standard	Concentration	Use When
1413 μS/cm (primary)	Medium-range standard	Always use as the first (or only) calibration point; covers most water treatment and environmental monitoring applications
84 μS/cm (low-range)	Low-concentration standard	Add for 2-point if measuring very low conductivity samples (high-purity RO water, distilled water)
12.88 mS/cm (high-range)	High-concentration standard	Add for 2-point if samples may exceed 2 mS/cm (seawater, highly concentrated process water, cooling tower blowdown)

Short press MODE to switch to Cond (conductivity) measurement mode

The display must show Cond before entering calibration. Conductivity calibration cannot be initiated in pH mode.

Rinse probe in pure water, pour 1413 μS standard into calibration vial, dip probe

Stir briefly to remove air bubbles from the conductivity cell, hold still.

Long press CAL (screen turns GREEN) — wait for stability — short press CAL

M icon appears confirming 1-point conductivity calibration. EC, TDS, salinity, and resistivity are all calibrated from this single step.

For 2-point: rinse — dip in 12.88 mS standard — long press CAL — wait — short press CAL

H icon appears. Do not power off between points.

Taking Measurements — Standard Procedure

Rinse probe thoroughly in pure water — shake off excess (never wipe)

Cross-contamination from the previous sample or calibration buffer will affect the next reading. Always rinse between samples.

Dip probe at least 1 inch (25 mm) into sample — stir briefly — hold still

The probe must be immersed deep enough to cover both the pH glass bulb and the conductivity sensor. Brief stirring removes air bubbles from the conductivity cell. Bubbles trapped in the cell produce falsely low conductivity readings.

Wait for the smiley face ☺ stability icon to appear AND remain

Do not record a reading until the stability indicator is present and steady. In pure water samples (RO, distilled, DI), pH stabilization may take 1–5 minutes — this is normal and does not indicate a problem.

Short press MODE to switch between parameters without removing from sample

All five parameters are available from a single immersion. Cycle through pH → Cond → TDS → Sal → Temp without lifting the probe. Record all parameters needed before removing.

Pure water pH measurement — the most common complaint resolved: Pure water (RO, DI, distilled) has very low ion concentration, which means the pH probe receives a very weak signal. Stabilization taking 1–5 minutes is expected and correct behavior. If needed, add Apera 3M KCl solution (AI1107) to the pure water at a ratio of 1:1000 (1 mL KCl per 1000 mL water) — this accelerates stabilization while minimally affecting the pH value. Pre-soak the probe in pH 4.00 buffer for 30 seconds before measuring pure water to condition the glass membrane.

Probe Care — The Most Important Maintenance Requirement

Storage — Always in 3M KCl, Never Dry or in Pure Water

Do not store the probe in pure water. This is the single most common cause of PC60 probe failure. Pure water (distilled, deionized, RO) dilutes the internal reference electrolyte and destabilizes the glass membrane. Storing dry is equally damaging. Always store the probe tip submerged in 3M KCl soaking solution — either in the included probe cap filled with KCl or in a dedicated storage bottle. If the probe was stored dry or in pure water, soak in 3M KCl for at least 15 minutes before calibrating.

Routine Cleaning (After Every Measurement)

Rinse probe in pure water from a wash bottle or container

Always rinse before and after each measurement session.

Shake off excess — never rub or wipe the glass membrane

Fingerprints and static electricity from wiping the pH glass membrane cause measurement errors. Shake off water droplets. If gentle dabbing is needed, use a lint-free Kimwipe with a dabbing (not rubbing) motion only on the sides of the probe, not on the glass bulb directly.

Replace probe cap with KCl solution inside for storage

The probe tip must remain moist in KCl between measurement sessions.

Deep Cleaning (Tough Contaminants)

Remove the sensor shield from the probe tip

Exposes the conductivity cell and pH glass for thorough cleaning.

Soak in probe cleaning solution (AI1166) or dilute detergent — 30 minutes

Loosens biological material, scale, oil, and process residues.

Gentle brush to remove remaining contaminants

Use a soft brush only. Never use abrasive materials on the glass membrane or conductivity electrodes.

Soak in 3M KCl for at least 1 hour after cleaning

Cleaning disrupts the reference junction and membrane equilibrium. A 1-hour KCl soak is required to restore proper electrode function before re-calibrating and measuring.

Rinse with pure water — re-calibrate before use

Always recalibrate after deep cleaning.

Parameter Settings (P1–P8) — Complete Reference

Access settings by powering OFF the instrument, then long-pressing MEAS. The display cycles P1 through P8. Short press MODE to advance, short press CAL to select, short press MODE to change value, short press CAL to confirm.

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	Automatic shut-off timer	5 min / 10 min / 30 min / Off	10 min
P3	TDS conversion factor (EC × factor = TDS)	0.40 – 0.90 in 0.01 steps	0.50
P4	Temperature compensation coefficient (%/°C)	0.00–4.00%/°C	2.0%/°C (linear)
P5	Conductivity unit display	μS/cm or mS/cm	μS/cm
P6	Temperature unit	°C or °F	°C
P7	Stability indicator sensitivity	Fast / Normal / Slow	Normal
P8	Factory reset	No / Yes	No — selecting Yes clears all calibration data
P3 TDS factor: the default 0.50 is appropriate for most natural waters. Adjust to 0.65–0.70 for KCl-dominant solutions (cooling tower blowdown with KCl treatment). Use the conductivity reading for the most reliable dissolved solids measurement — TDS is a calculated approximation.

Probe Replacement

The PC60-E is a consumable. Replace when: pH stabilization is persistently slow despite proper KCl soaking and cleaning; calibration requires an unusually large slope correction; or readings are inconsistent across replicate measurements on the same sample despite correct technique.

Screw off the probe ring counterclockwise

The probe ring threads counterclockwise to remove.

Unplug old probe — align new probe carefully before plugging in

The connector has a correct orientation. Never force the probe connector. Damage from forced insertion is not covered under warranty. Align first, then press in gently until seated.

Screw probe ring back on clockwise — soak new probe in KCl 5–15 minutes

New probes need KCl conditioning before calibration and measurement.

Consider factory reset (P8 = Yes) to clear old calibration data

Old calibration data from the previous probe is stored in memory and may produce inaccurate results with the new probe. Factory reset clears all calibration — then recalibrate with fresh buffers and standards.

Troubleshooting

Symptom	Likely Cause	Resolution
pH reading drifts continuously, won’t stabilize	Probe stored in pure water or dry; glass membrane dehydrated	Soak probe in 3M KCl for 15–30 minutes; recalibrate. If persistent after 30 min soak, replace probe.
pH reading unstable in pure water (5+ minutes)	Normal behavior — low ion concentration weakens signal	Add 1 mL KCl per 1000 mL sample; pre-soak probe in pH 4.00 buffer for 30 sec before measuring. Not a fault.
Calibration fails or buffer not recognized	Wrong buffer series selected in P1; contaminated buffer solution; probe dirty	Check P1 setting (USA vs NIST); replace contaminated buffer solutions; deep clean probe and soak in KCl 1 hour; recalibrate
EC/TDS reads zero or very low	Air bubble trapped in conductivity cell; probe not immersed deep enough	Stir probe vigorously in sample to expel bubbles; ensure probe immersed at least 25 mm; check conductivity calibration
All readings off by consistent offset	Calibration data from old probe still in memory after probe replacement	Factory reset (P8 = Yes); recalibrate with fresh standards
Display shows “Err”	Probe not connected; damaged probe connector; sample outside measurement range	Check probe connection; verify probe ring is fully threaded; check if sample is within specified ranges
Battery life short	Backlight left on; auto-shutoff disabled	Toggle backlight off (short press MEAS during measurement); verify P2 auto-shutoff is set appropriately

Application Matrix — Water Treatment Context

Application	Primary Parameters	Typical Ranges	Notes
RO system performance	TDS (feed vs. permeate)	Feed: 200–800 mg/L; Permeate: <50 mg/L	TDS rejection = (feed–permeate)/feed × 100%. >95% is typical for a healthy membrane.
Softener influent/effluent	EC, TDS, pH	EC change minimal; pH may rise slightly	Softening exchanges Ca/Mg for Na — TDS changes little. Verify with hardness test, not TDS alone.
Cooling tower water	EC, TDS, pH	EC 1,000–5,000 μS/cm; pH 7.0–9.0	High EC indicates need for blowdown. pH outside range affects scale/corrosion balance and biocide efficacy.
Pool & spa	pH, TDS	pH 7.2–7.6; TDS <1,500 mg/L (pool)	pH is the primary driver of chlorine efficacy and equipment corrosion. TDS accumulates over time — drain/refill when needed.
Hydroponics nutrient solution	EC, pH	EC 0.8–3.0 mS/cm; pH 5.5–6.5	EC tracks nutrient concentration; pH governs nutrient availability. Both must be monitored and adjusted daily in active systems.
Aquaculture / recirculating systems	pH, EC, Temp	pH 6.5–8.5 (species-dependent); Temp varies	TDS accumulates in recirculating systems; EC is the fastest indicator. Salinity mode relevant for marine species.
Wastewater process control	pH, EC	Influent pH 6–9; EC highly variable	pH critical for biological treatment; EC indicates dissolved solids load. Use for rapid field screening before lab analysis.

PC60 vs Hach DR900 — Complementary, Not Competing

The most important context for water quality professionals: the PC60 and the Hach DR900 (or DR300 series) are not alternatives — they measure completely different parameters using different physics and are both needed for a complete water quality picture.

PC60 vs DR300/DR900 — DIFFERENT MEASUREMENT PRINCIPLES

Apera PC60 — Electrochemical

Measures: pH, EC, TDS, Salinity, Temp
How: Direct probe contact; ion exchange (pH) and conductance (EC)
Cannot measure: Chlorine, iron, phosphate, ammonia, nitrate, COD
Best for: Process monitoring, RO performance, nutrient solutions, quick field screening

Hach DR300/DR900 — Colorimetric

Measures: Chlorine, iron, phosphate, ammonia, nitrate, COD, bromine, manganese…
How: Light absorbance of chemically treated samples
Cannot measure: pH, EC, TDS, salinity directly
Best for: Chemical parameter compliance, contaminant monitoring, disinfectant residuals

A complete water treatment monitoring program uses both instrument types. The PC60 tells you the ionic and physical water quality; the DR300/DR900 tells you the chemical contamination and disinfection status.

What’s in the Kit

Item	Qty	Purpose
AI316 / PC60 tester (with PC60-E probe installed)	1	Instrument; probe pre-installed and conditioned in KCl
Carrying case (hard-shell)	1	Field transport; holds instrument and all accessories securely
pH 4.00 calibration solution	1 bottle	Low-point pH calibration; 2-point or 3-point calibration
pH 7.00 calibration solution	1 bottle	Midpoint pH calibration; always calibrate here first
pH 10.01 calibration solution	1 bottle	High-point pH calibration; 3-point calibration for alkaline range
84 μS/cm conductivity calibration solution	1 bottle	Low-range conductivity calibration
1413 μS/cm conductivity calibration solution	1 bottle	Primary conductivity calibration standard
Calibration vials (labeled)	Set	Pour calibration solutions here; reusable per buffer limits
3M KCl soaking solution	1 bottle	Probe storage; in probe cap during normal storage
4 × AAA batteries	Installed	Pre-installed; pull insulation slip before first use
Quick start guide / instruction card	1	Laminated quick reference; keeps in carrying case lid
No additional accessories required for immediate use. Probe cleaning solution (AI1166) and replacement probes (PC60-E) are available separately from Apera Instruments.

Apera Instruments AI316 PC60 — $147.58 — Amazon Overall Pick

5-in-1: pH, EC, TDS, Salinity, Temp • IP67 • Replaceable probe • Complete kit. 300+ bought/month.