Hanna HI98312 Portable High-Range EC/TDS/°C Meter

Overview

The Hanna HI98312 is a portable, field-deployable multi-parameter meter engineered for precise, real-time measurement of electrical conductivity (EC), total dissolved solids (TDS), and temperature in aqueous solutions. It operates on the fundamental principle of conductometric analysis: applying an alternating current across a graphite dual-cell electrode to measure solution resistance, which is then converted to EC (mS/cm) using cell constant calibration. TDS is derived via linear conversion using a user-selectable factor (0.45–1.00), reflecting the ionic composition of the sample—critical for applications where salinity, mineral content, or nutrient concentration must be quantified with laboratory-grade reliability outside controlled environments. Designed for rugged use in agriculture, aquaculture, hydroponics, wastewater monitoring, and environmental fieldwork, the HI98312 integrates automatic temperature compensation (ATC) with a programmable β coefficient (0.0–2.4 %/°C) to correct for thermal drift in non-standard electrolytes—ensuring traceable accuracy across diverse sample matrices and ambient conditions.

Key Features

• Integrated graphite dual-cell conductivity probe (HI73311) with embedded NTC thermistor—minimizes polarization error and enables rapid equilibration in high-ionic-strength or viscous samples.
• Auto-recognizing single-point calibration with factory-traceable internal standards: 12.88 mS/cm for EC and 6.44 ppt for TDS—eliminates manual calibration code entry and reduces operator error.
• Dual-line LCD display with contextual on-screen prompts guiding users step-by-step through calibration and measurement protocols—compliant with GLP documentation best practices.
• Two-button operation architecture: dedicated “Mode” and “Cal/Read” keys ensure intuitive navigation without menu diving—optimized for gloved or field-conditioned use.
• Battery Error Prevention System (BEPS): actively monitors voltage during measurement cycles and halts readings if power falls below operational threshold—preventing invalid data capture due to low battery.
• Automatic shutdown after 8 minutes of inactivity conserves battery life while maintaining readiness for immediate deployment—critical for intermittent sampling in remote locations.

Sample Compatibility & Compliance

The HI98312 is validated for use with natural waters (freshwater, brackish, effluent), nutrient solutions, soil extracts, and industrial process streams within its specified EC range (0.00–20.00 mS/cm). Its graphite electrode design resists fouling from organic films and particulates better than stainless-steel or platinum alternatives—extending service intervals in turbid or biofilm-prone environments. While not certified to IEC 61000-6-3 or ATEX standards, the instrument meets general-purpose safety requirements per IEC 61010-1 for handheld electrical equipment used in non-hazardous locations. Its measurement methodology aligns with ASTM D1125 (Standard Test Methods for Electrical Conductivity and Resistivity of Water) and ISO 7888 (Water quality — Determination of electrical conductivity), supporting data integrity in QA/QC workflows requiring auditable traceability.

Software & Data Management

As a standalone field instrument, the HI98312 does not feature onboard data logging or USB connectivity. However, its stable analog output behavior and repeatable endpoint detection support integration into manual logbooks, LIMS-compatible paper-based reporting, or external digital recording via timed observation protocols. The inclusion of programmable TDS conversion factors and β compensation coefficients allows users to maintain method consistency across batches and operators—essential for compliance with USP , EP 2.2.38, and FDA 21 CFR Part 11–aligned documentation systems when paired with controlled procedural SOPs.

Applications

• Agricultural irrigation management: monitoring EC and TDS of nutrient reservoirs to prevent salt accumulation and osmotic stress in greenhouse crops.
• Aquaculture system health assessment: tracking conductivity shifts as early indicators of salinity imbalance or waste buildup in recirculating tanks.
• Environmental field surveys: rapid screening of surface water conductivity for watershed baseline studies or pollution incident response.
• Wastewater treatment plant operations: verifying effluent salinity compliance prior to discharge and assessing membrane filtration performance via feed/retentate EC differentials.
• Hydroponic nutrient solution control: ensuring consistent ionic strength across growth stages by correlating EC with fertilizer dosing schedules.

FAQ

What calibration standards are required for routine operation?
The HI98312 uses pre-programmed internal reference points: 12.88 mS/cm for EC (recommended standard: HI7030L) and 6.44 ppt for TDS (recommended standard: HI70038). These are traceable to NIST-certified solutions and eliminate the need for manual calibration code input.
Does the instrument support variable TDS conversion factors?
Yes—users can adjust the TDS conversion factor between 0.45 and 1.00 to match the dominant ion profile of their sample matrix (e.g., 0.50 for NaCl-dominated solutions, 0.70 for mixed-salt irrigation water).
How is temperature compensation implemented?
The meter applies linear ATC using a user-configurable β coefficient (0.0–2.4 %/°C), enabling correction for non-NaCl electrolytes where standard 2.0 %/°C compensation introduces systematic bias.
Is the electrode replaceable without tools?
Yes—the HI73311 probe is a snap-in modular assembly; replacement requires no screwdrivers or adhesives and maintains full calibration integrity upon insertion.
What is the operating temperature limit for reliable measurements?
The instrument functions continuously at ambient temperatures from 0 to 50°C (32–122°F) with relative humidity up to 100%, though prolonged exposure above 40°C may accelerate battery discharge and affect long-term sensor stability.