The Apera PH400S (AI421) is a professional handheld pH meter designed for commercial cultivation, hydroponics, and fertigation quality control. Its 201T-S combination electrode measures pH and temperature simultaneously, while automatic calibration, electrode diagnostics, and a stability indicator support reliable readings. USB connectivity enables data export and external power, and the built-in GLP logger stores timestamped measurements for quality-control records.
• Brand: Apera Instruments
• Model / SKU: PH400S / AI421
• pH Range: −2.00 to 19.99 pH
• Accuracy: ±0.01 pH ±1 digit
• Included Electrode: 201T-S combination pH/temperature probe
• Temperature Compensation: Automatic or manual, 0–100°C
• Calibration: Automatic 1–5-point calibration with buffer recognition
• Data Storage: 500 GLP records with date and time stamps
• Connectivity: USB data export and external power
• Protection Rating: IP57 waterproof and dustproof
• Power Supply: 4 × AA batteries
• ORP Capability: Supported with a separately purchased compatible ORP electrode
Key Advantage: The PH400S combines accurate pH testing with 500 timestamped records and USB data export, making it suitable for facilities that need documented nutrient-solution checks rather than relying on handwritten logs.