Premium Series Portable pH Meter for Micro Samples with GLP Data Logger

What It Is

The Apera PH8500-MS (SKU: AI5554) is a field-grade portable pH meter from Apera's Premium Series, purpose-built around the measurement of small-volume and semi-micro liquid samples. It ships as a complete kit centered on the Swiss LabSen® 243-6 combination pH/temperature electrode — a 100mm-long, 6mm-diameter semi-micro probe with low membrane resistance (<350MΩ) and a built-in 30KΩ NTC thermistor for automatic temperature compensation (ATC).

The meter's measurement range covers 0–14 pH at ±0.01 accuracy, with a sample temperature range of 0 to 100°C (32 to 212°F). The minimum measurable volume is 60µL when using the included semi-micro container, and standard small-volume measurement works reliably from 0.2mL and up — making this unit practical for test tubes, extraction vessels, and other confined sample formats that a standard bulb-tip electrode cannot reach.

Apera Instruments has been developing water analysis sensors and instruments since 1991 and has deployed product in over 50 countries. The PH8500-MS carries a 3-year instrument warranty and a 6-month probe warranty from Apera.

Who It's For

Commercial cannabis and hemp cultivators who need precise, documented pH data across multiple stages of production — from tissue culture and extract quality checks to fertigation solution verification and coco/media leachate testing — will find the AI5554 purpose-built for those use cases. Its ability to read samples as small as 60µL makes it the right tool anywhere a standard-diameter probe won't fit or would require too large a draw volume.

It's equally appropriate for QA/QC teams operating in licensed processing and extraction facilities, where GLP-compliant record-keeping is a compliance expectation rather than a convenience. The 500-record onboard data log with manual or auto-storage modes and USB data output means measurement records can be exported to a PC without transcription errors — a meaningful advantage in audit-ready environments.

The foldable stand and IP57 waterproof rating allow the meter to be used as a benchtop instrument in the lab or carried into the canopy and production floor without concern for water or splash exposure. Operators who move between wet environments — fertigation rooms, propagation areas, extraction labs — will appreciate both the silicone-wrapped grip and the rugged construction.

Key Features

The LabSen® 243-6 electrode at the core of this kit is built on Swiss sensor technology. Apera's proprietary blue-gel inner electrolyte solution is non-flowing and does not generate air bubbles, allowing the electrode to function accurately even when held inverted — a common position when measuring small containers or test tubes. The long-life reference system uses a glass tube, AgCl granules, and a silver reference wire with a cotton-packed tip that isolates the reference chemistry from temperature-driven electrolyte shifts, extending electrode service life.

Meter intelligence centers on a self-diagnosis system that flags out-of-range readings and electrode invalidation in real time, prompting corrective action before a bad reading gets logged. Automatic calibration recognizes pH 1.68, 4.00, 7.00, 10.01, and 12.45 buffer standards across 1–3 calibration points, with slope data displayed post-calibration. The display shows calibration due date and last calibration record — both GLP requirements.

The large white backlit LCD delivers clear readings in low-light grow environments. The meter is powered by AA batteries, and the IP57-rated body with soft silicone case handles wet conditions without compromising electronics. Data is stored in 500 GLP-standard records and exported via USB, eliminating manual transcription from the measurement workflow.

How It Fits a Commercial Cultivation Build

pH control is non-negotiable at commercial scale — drift of even 0.2 pH units in a recirculating fertigation system can lock out critical micronutrients and tank a run. The AI5554 gives cultivation teams a portable, accurate instrument they can use across multiple zones without relying on a single fixed benchtop unit or waiting for lab results.

For operations running coco, rockwool, or hydroponic systems, the meter handles both nutrient solution checks and small-volume substrate leachate samples — the 60µL floor means even tight sample volumes from a 1:1.5 leachate extraction are measurable. Tissue culture and propagation labs benefit from the micro-sample capability and the GLP log for maintaining documented calibration records.

The USB data output means pH measurements can be exported directly into a crop management spreadsheet or IPM log with timestamps, supporting both internal QA programs and state-level compliance documentation. For multi-site operators, the portable form factor means one meter type can standardize pH protocol across facilities rather than mixing instrument brands and accuracy tiers.