The Apera Instruments SX731 is a multi-parameter portable meter designed for laboratory-grade measurement of pH, ORP (redox potential), conductivity (EC), TDS, salinity, and resistivity in a variety of water solutions. Built for field and lab use, it features IP57 dust and water protection, a rugged design, and a hard carrying case, making it a reliable tool in harsh environments.
With high-precision electrodes including the 201T-S pH/Temp. electrode, 301Pt-S ORP electrode, and the 2301T-S conductivity/temp. electrode featuring BPB (Brush-resistant Platinum Black) technology, the SX731 delivers fast, accurate, and repeatable results. The digital filtering technology ensures quick response and improved measurement accuracy. Both the pH and conductivity electrodes offer automatic temperature compensation for stable readings across varying conditions.
This meter allows easy switching between EC, TDS, salinity, and resistivity. It also features 1 to 3-point pH calibration and 1-point EC calibration, with storage for up to 300 data sets.
Key Features:
✔ Multi-parameter measurement – pH, ORP, EC, TDS, salinity, resistivity, and temperature
✔ Includes 3 high-quality electrodes – pH, ORP (no calibration required), and EC/temp.
✔ Brush-resistant Platinum Black (BPB) conductivity electrode with wide range (0–200 mS/cm)
✔ Automatic temperature compensation for pH and conductivity
✔ Quick, accurate ORP readings using a platinum sensor – easy to clean and maintain
✔ Fast calibration – 1-3 point pH and 1-point EC
✔ Digital filter technology – boosts response time and accuracy
✔ Stores 300 data sets – recall results easily during field work
✔ IP57-rated waterproof and dustproof – ideal for rugged environments
✔ 3-year manufacturer’s warranty (6 months for electrodes)
Complete Set Includes:
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SX731 multi-parameter meter
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201T-S pH/Temp. electrode
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301Pt-S ORP electrode (platinum sensor)
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2301T-S conductivity/temp. electrode (BPB technology)
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Calibration solutions:
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pH 4.00 (50 ml)
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pH 7.00 (50 ml)
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pH 10.01 (50 ml)
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1413 µS EC solution
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User manual
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2x AA batteries
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Screwdriver
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Rugged carrying case
| Conductivity (EC) | |
| Accuracy | Device: ±1.0 F.S, Total: ±1.5% F.S |
|---|---|
| Electrode Constant | 0.1 / 1 / 10 cm-1 |
| Measuring Range | Conductivity: (0.00 to 19.99) μS/cm, (20.0 to 199.9) μS/cm (200 to 1999) μS/cm, (2.00 to 19.99) mS/cm (20.0 to 199.9) mS/cm TDS: (0 to 100) g/L; Salinity: (0 to 100) ppt Resistivity: (0 to 100) MΩ·cm |
| Reference Temperature | 25°C, 20°C, and 18°C |
| Resolution | 0.01/0.1/1 μS/cm; 0.01/0.1 mS/cm |
| Temp. Compensation | (0 to 50) °C (automatic) |
| More | |
| Data Content | Serial number, measured value, measuring unit and temperature |
| Data Storage | 300 data sets |
| Dimensions and Weight | Meter: (65×120×31) mm/180 g Complete set: (255×210×50) mm/1490 g |
| IP Rating | IP57 |
| Power Supply | 2 AA batteries (1.5V x2) |
| Quality and safety certification | CE, ISO 9001:2015 |
| pH | |
| Accuracy | Instrument: ±0.01 pH; Total: ±0.02 pH |
| Input Current | ≤2×10-12 A |
| Input Impedance | ≥1×1012Ω |
| Measuring Range | (-2.00 to 19.99) pH |
| Resolution | 0.1/0.01 pH |
| Stability | ±0.01 pH/3h |
| Temp. Compensation | (0 to 100) °C (automatic) |
| Redox Potential (ORP) | |
| Accuracy | Device: ±0.1% FS, Total: ±15 mV |
| Measuring Range (mV/ORP/EH) | -1999mV to 0 to 1999mV |
| Resolution | 1 mV |
Everything is perfect. I would recommend!
