Hanna HI98318 Portable EC/TDS/°C Meter

Overview

The Hanna HI98318 is a compact, handheld multiparameter meter engineered for precise, field-ready measurement of electrical conductivity (EC), total dissolved solids (TDS), and temperature in aqueous solutions. Based on the principle of two-electrode conductometric measurement—using a graphite dual-pole conductivity sensor—the instrument delivers stable, low-polarization response across diverse sample matrices, including nutrient solutions, hydroponic reservoirs, wastewater effluents, irrigation water, and soil leachates. Its integrated temperature sensor enables automatic temperature compensation (ATC) using a programmable β coefficient of 1.9 %/°C, conforming to standard linear compensation models used in environmental and agricultural testing protocols. Designed for rugged daily use in non-laboratory settings, the HI98318 meets the functional requirements of ISO 7888 (water quality — determination of electrical conductivity) and supports routine compliance with EPA Method 120.1 and ASTM D1125 for conductivity and TDS estimation in field-deployed water quality monitoring.

Key Features

• Integrated graphite dual-pole conductivity electrode with built-in NTC temperature sensor—eliminates inter-electrode polarization and ensures rapid equilibration in low-conductivity or high-viscosity media.
• Simultaneous real-time display of EC (mS/cm), TDS (ppm), and temperature (°C/°F) on a large dual-line LCD with intuitive icon-driven prompts.
• One-button automatic single-point EC calibration with auto-recognition of standard points (1.41 mS/cm or 5.00 mS/cm); compatible with Hanna’s traceable calibration standards (e.g., HI7031, HI7030, HI5036).
• User-selectable TDS conversion factors (0.50 or 0.70) aligned with industry-specific reporting conventions—enabling accurate interpretation for hydroponics (500 ppm NaCl equivalent) and municipal water (700 ppm NaCl equivalent).
• Automatic temperature compensation (ATC) with adjustable β factor (default 1.9 %/°C), compliant with common regulatory frameworks for conductivity normalization.
• Low-power design with BEPS (Battery Error Prevention System) to prevent erroneous readings during voltage drop; auto-off after 8 minutes of inactivity.
• Rugged, IP67-rated housing (when sealed) suitable for humid, outdoor, or greenhouse environments; operating range: 0–50°C, ≤100% RH.

Sample Compatibility & Compliance

The HI98318 is validated for direct immersion measurement in liquid samples with conductivity up to 6.00 mS/cm—including nutrient solutions (Hoagland, Peters, General Hydroponics), surface water, groundwater, reverse osmosis permeate and concentrate streams, and agricultural runoff. It is not intended for use with organic solvents, strong acids/bases (>pH 12), or slurries containing suspended solids >50 µm. The device supports GLP-aligned workflows through stable calibration memory, ATC traceability, and documented sensor response characteristics. While not FDA 21 CFR Part 11–compliant (as it lacks audit trail or user authentication), its calibration and measurement repeatability align with ISO/IEC 17025 internal quality control requirements for field instrumentation used in accredited environmental testing laboratories.

Software & Data Management

The HI98318 operates as a standalone, microprocessor-controlled instrument without Bluetooth, USB, or PC connectivity. All calibration data, TDS factor selection, and unit preferences are retained in non-volatile memory. No proprietary software or drivers are required. Users maintain traceability via manual logbook entry of calibration date, standard lot number (e.g., HI5036 Lot#XXXXX), and measured values. For laboratories requiring digital data capture, Hanna recommends pairing the HI98318 with external documentation tools such as LIMS-compatible spreadsheets or validated paper-based QC forms referencing ISO 17025 Clause 7.7 (results reporting).

Applications

• Hydroponics & Controlled Environment Agriculture: Monitoring EC and TDS in recirculating nutrient tanks to maintain optimal ion concentration and prevent osmotic stress in leafy greens, tomatoes, and cannabis cultivars.
• Environmental Field Screening: Rapid assessment of conductivity anomalies in stream monitoring, wetland restoration projects, and landfill leachate collection systems per USGS NWIS protocols.
• Water Treatment & RO System Management: Calculating concentration ratios (CR) and rejection rates by comparing feed, permeate, and concentrate EC values in small-scale membrane systems.
• Educational Laboratories: Teaching fundamental principles of solution conductivity, ion dissociation, and temperature dependence in undergraduate chemistry and environmental science curricula.
• Soil Testing Support: Measuring EC of saturated paste extracts (SAR, CEC estimation) and irrigation water compatibility assessments per USDA NRCS guidelines.

FAQ

Does the HI98318 require electrode replacement?
No—the graphite conductivity sensor and NTC temperature probe are permanently integrated and non-replaceable. The sensor is designed for extended service life under normal field use conditions.
Can I switch between TDS conversion factors during measurement?
Yes—factor selection (0.50 or 0.70) is configurable prior to measurement and remains active until manually changed.
Is the HI98318 compliant with ASTM D1125 or ISO 7888?
It implements measurement principles and compensation algorithms consistent with these standards; however, formal compliance verification requires system-level validation per laboratory SOPs.
What is the recommended calibration frequency?
Daily calibration is advised for critical applications (e.g., nutrient dosing control); weekly calibration suffices for general environmental screening when using stable standards and controlled storage.
Can the HI98318 measure pH?
No—this is an EC/TDS/°C-only meter. For combined pH/EC/TDS measurement, consider the Hanna HI98107 or HI98130 series.