Lab-grade pH measurement in high-temperature, caustic, and chemically aggressive solutions — field-ready, IP57-rated.
The Apera PH8500-HT (AI5566) is a professional-grade portable pH meter built specifically for high-temperature liquids and caustic solutions, equipped with the Swiss LabSen 863 pH/Temp electrode featuring a PHY glass membrane, anti-clogging PTFE junction, and silver-ion-trap reference system. IP57-rated, GLP-compliant, and built for the conditions standard meters fail in.
Most portable pH meters are rated for general aqueous solutions — clean reservoir water, standard nutrient solutions, mild buffers. Put a standard electrode into a hot, caustic, or chemically complex liquid and you get drift, clogged junctions, shortened probe life, and readings you can't trust. The Apera PH8500-HT is engineered specifically for those environments.
The included Swiss LabSen 863 pH/Temp electrode uses a PHY glass membrane that resists chemical corrosion far beyond what standard glass can handle, paired with an anti-clogging PTFE ring junction that prevents the junction blockages common in complex chemistry. The silver-ion-trap reference system maintains reference potential stability even as sample composition shifts. Solution temperatures up to 130°C (266°F) are within spec. For operators running hot nutrient tanks, aggressive pH-down concentrates, caustic cleaning cycles, or process water with elevated dissolved solids, this is the tool built for that workload.
Licensed cannabis and hemp cultivation operations that run recirculating systems, top-feed coco, or large-scale hydro infrastructure deal with pH reads across a range of solution types and temperatures — not just clean RO at room temperature. When your fertigation solution is warm coming off a reservoir, when you're spot-checking a concentrated stock solution, or when your SOPs require documented, GLP-compliant pH records that hold up to audit, a general-purpose meter falls short.
The PH8500-HT is also a fit for operations that batch-mix nutrients at scale, work with aggressive pH-adjustment chemicals, or maintain a cultivation facility's process equipment where caustic cleaning agents require periodic pH verification. Extraction and post-harvest facilities handling ethanol or solvent-based processes may find the high-temperature and chemical-resistance specs equally relevant. Anywhere a standard meter gets destroyed or gives unreliable readings, this unit is the correct specification.
The PH8500-HT measures pH across a −2.00 to 16.00 pH range at 0.01 pH resolution, with ±0.01 pH accuracy. Automatic temperature compensation (ATC) runs continuously via the included MP500 external temperature sensor, keeping readings corrected as solution temperature climbs. Calibration is 1-to-3 point auto-calibration with auto-recognition of standard buffer values (pH 1.68, 4.00, 7.00, 10.01, 12.45). The meter displays electrode slope after calibration — a direct indicator of electrode health.
GLP-standard data management stores up to 500 measurement sets in auto or manual logging modes. USB output connects to Apera's web-based PC-Link software (Chrome, Edge, Firefox — no installation required), which exports stored data to CSV or PDF reports complete with calibration date, electrode slope, offset, and meter serial number. For operations where pH records are part of an SOP audit trail, that documentation chain is already built in.
Intelligent self-diagnosis flags out-of-range readings and electrode invalidation before they become data integrity problems. Auto power-off preserves battery life. The large backlit LCD displays pH and temperature simultaneously, and a stability icon confirms the reading has settled before logging.
The IP57-rated housing means the meter can be submerged in up to 1 meter of water for 30 minutes — standard for a grow floor or process environment where wet conditions are routine, not exceptional. A soft silicone grip case absorbs impact and gives secure handling in gloved hands or in humid rooms. A foldable stand lets the meter transition from handheld field use to stable benchtop operation without a second instrument.
Power is 3 AA batteries — widely available, no proprietary charging system. The kit ships with the LabSen 863 electrode, MP500 temperature sensor, pH calibration solutions (4.00, 7.00, 10.01), electrode storage solution, carrying case, USB cable, and documentation. ORP measurement is supported when paired with a 301Pt-C ORP electrode (sold separately). The PH8500-HT carries a 3-year instrument warranty and 6-month probe warranty direct from Apera Instruments.
| Model | PH8500-HT |
| SKU | AI5566 |
| pH Measuring Range | −2.00 to 16.00 pH |
| pH Resolution | 0.01 / 0.1 pH (selectable) |
| pH Accuracy | ±0.01 pH ±1 digit |
| Solution Temp Range (Electrode) | Up to 130°C (266°F) |
| Temperature Compensation | Automatic (ATC) or manual, 0–100°C |
| Electrode | Swiss LabSen 863 pH/Temp — PHY glass membrane, PTFE junction, silver-ion-trap reference |
| Calibration | 1–3 point auto; auto-recognizes pH 1.68, 4.00, 7.00, 10.01, 12.45 |
| Data Storage | 500 GLP data sets; auto/manual logging; USB output |
| Waterproof Rating | IP57 |
| Power | 3 × AA batteries |
Standard pH electrodes use glass membranes and junction materials that degrade rapidly in high-temperature or chemically aggressive liquids — the glass softens, the junction clogs, and the reference potential drifts. The LabSen 863 uses a PHY glass membrane rated for chemical resistance and high heat, a PTFE ring junction that resists clogging from complex chemicals, and a silver-ion-trap reference system that maintains stable reference potential in those same conditions. Using a standard electrode in these environments would produce unreliable readings and a shortened probe lifespan.
The LabSen 863 electrode is rated for solutions up to 130°C (266°F). The meter body's automatic temperature compensation (ATC) operates across 0–100°C. For solution temperatures between 100°C and 130°C, manual temperature compensation can be entered. Always verify your specific process conditions against the full electrode spec sheet before deployment.
The meter stores up to 500 measurement records in GLP format — each record includes the pH value, temperature, date, and time. Storage can be set to auto (timed intervals) or triggered manually. USB output connects to Apera's web-based PC-Link software, which runs in Chrome, Edge, or Firefox with no software installation required. From there you can view real-time charts and export data to CSV or PDF reports that include calibration date, electrode slope, offset, and meter serial number — suitable for SOP documentation and compliance records.
Yes, ORP measurement is supported by the PH8500-HT meter body. You need to pair it with a compatible ORP electrode — the 301Pt-C is the Apera-specified option, sold separately. The LabSen 863 included with the kit measures pH and temperature only.
The PH8500-HT's built-in self-diagnosis monitors electrode condition and flags electrode invalidation directly on screen. After each calibration, the meter displays electrode slope — a reading outside the normal range (typically 85–105%) is an early indicator of degradation before the electrode fully fails. Apera's 6-month probe warranty covers manufacturing defects; electrode service life in caustic or high-temperature service will depend on frequency of use and solution chemistry.
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