Hanna Instruments DiST 6 HI98312 Portable EC/TDS/temperature combo meter
The Hanna Instruments DiST® 6 HI98312 is a portable waterproof combo meter for measuring electrical conductivity (EC), total dissolved solids (TDS) and temperature in liquid samples. It can be used to test water quality, monitor nutrient solutions and perform routine analysis in agricultural, hydroponic, aquarium and laboratory settings.
The electrical conductivity of a liquid is a measure of how easily electricity is conducted and depends on the concentration of dissolved ions. Total dissolved solids is an estimate of the dissolved material in a liquid, based on the conductivity of the liquid and multiplied by a conversion factor. Temperature is also measured because it alters the readings of conductivity. The HI98312 puts all three measurements into one handheld instrument, allowing users to check several aspects of a liquid without having to use separate meters.
How HI98312 Measures EC, TDS and Temperature
The meter is for measuring electrical conductivity through a replaceable graphite electrode. The instrument measures how well the electrode can carry an electrical current when submerged in a liquid. Salts and nutrient compounds have ions dissolved in them that help conduct electricity.
The HI98312 converts the measured conductivity to a TDS value using a conversion factor which can be selected between 0.45 and 1.00. The TDS readings are estimates, not direct measurements of the mass of each dissolved substance. Different liquids contain different combinations of dissolved substances.
An integrated temperature sensor measures the temperature of the sample. Automatic Temperature Compensation (ATC) automatically compensates for temperature variations in EC and TDS readings. The temperature coefficient can be set from 0.0 to 2.4 %/°C depending on the measurement requirements.
Key features and practical applications
- A single portable instrument measures three measurement parameters, EC, TDS and temperature.
- High-range EC measurement: The 0.00 to 20.00 mS/cm range is for testing liquids with relatively high conductivity.
- Replaceable graphite electrode: The HI73311 electrode is replaceable as needed. Graphite does not get contaminated by salt deposits and thus keeps the measurements consistent.
- Automatic temperature compensation: Adjusts conductivity and TDS readings for temperature, allowing more accurate comparisons between different samples.
- Adjustable TDS Conversion Factor – User can select a factor from 0.45 to 1.00 to better match the liquid being tested.
- One-point automatic calibration: Easy calibration with the right conductivity or TDS reference solution.
- Waterproof, floating housing: Designed for use around liquids, the housing floats if dropped in water.
- Hold function: Pause the displayed reading for ease of recording.
Battery indicators and automatic off: Users can see the battery status and help save power when the meter is not being used.
Technical specifications
- The brand is Hanna Instruments.
- Product line DiST® 6 series
- HI 98312 Model:
- Product Type: Portable EC/TDS/Temperature Combo Meters
- EC Measuring Range: 0.00-20.00 mS/cm
- EC resolution 0.01 mS/cm
- Accuracy EC: ±2% of full scale
- EC calibration: Automatic, 1 point at 12.88 mS/cm
- TDS measurement range: 0.00 ~ 10.00 ppt (g/L)
- TDS resolution: 0.01 ppt (g/L)
- TDS Accuracy: ±2% of full scale reading
- TDS calibration: Auto, 1 point at 6.44 ppt (g/L)
- EC to TDS conversion factor: Varies from 0.45 to 1.00
- Temperature range: 0.0 to 60.0 °C (32.0 to 140.0 °F)
- Temperature Resolution 0.1 °C (0.1 °F)
- Temperature accuracy: ±0.5 °C (±1.0 °F)
- Temperature Compensation: Automatic, coefficient adjustable 0.0 to 2.4 %/°C
- Electrode: HI73311 replaceable graphite EC/TDS electrode.
- Battery: 4 x 1.5 V batteries.
- Battery life: Up to 100 hours of continuous use.
- Automatic shut-off: When not in use for 8 minutes
- Operating environment 0 to 50 °C, maximum relative humidity 100
- Dimensions: 163 x 40 x 26 mm
- Weight: ~100g
Appropriate applications and compatibility
HI98312 can be used anywhere EC, estimated TDS and temperature measurements offer useful information about a liquid.
- Hydroponics and agriculture: Monitor changes in dissolved ion concentrations by checking the conductivity of nutrient solutions and irrigation water.
- Water quality testing Compare sample to sample conductivity readings or monitor changes while treating the water.
- Aquariums and aquaculture: Conductivity is a measure of changes in water composition. Water suitability for a particular species is not determined by EC alone.
- Laboratories: Check properly for conductivity and TDS of suitable liquid samples on routine basis.
- Industrial water systems: Measure conductivity as part of water management procedures where the range of the instrument is appropriate.
The HI98312 measures EC, TDS and temperature. It does not directly identify individual dissolved substances, or specific nutrient concentrations or pH. Additional instruments or analytical methods are required when those results are needed.
Calibration, operation, and maintenance
Before a measurement check the electrode and wash with a suitable clean liquid. Turn on the meter and insert the electrode into the sample as directed by the manufacturer. Write down the result after the reading settles. Rinse the electrode between samples to minimize the risk of cross-contamination.
Calibrate the meter using a suitable reference solution and the calibration procedure as stated in the manual. The specified point is 12.88 mS/cm for EC calibration and 6.44 ppt for TDS calibration. Use the correct solution for the mode of measurement chosen and do not contaminate the reference solution with the sample.
Keep the electrode clean and replace it if it no longer gives reliable readings. Replace the batteries as required and store the instrument according to the manufacturer’s instructions. Automatic shut-off function for saving battery power during normal use.
Components included
The Hanna Instruments HI98312 comes with:
- replaceable EC/TDS graphite electrode HI73311
- Electrode Removal Tool HI73128
- Bags of standard solution for EC conductivity
- Sachets of TDS standard solution
- 4 x 1.5 V batteries
- Certificate of instrument quality
- Manual of the user
See the supplier’s packaging information to find out what’s in the particular kit being shipped.
DiST 5 or DiST 6?
The HI98312 DiST 6 is rated for a higher range of conductivity and TDS than the Hanna Instruments DiST 5 HI98311. HI98311 measures EC up to 3999 µS/cm and TDS up to 2000 ppm. HI98312 measures EC up to 20.00 mS/cm and TDS up to 10.00 g/L.
For comparison 1 mS/cm = 1000 µS/cm. So the HI98312 is more appropriate when the samples may be outside the measurement range of the DiST 5. Both meters measure temperature and both use replaceable graphite electrodes but the choice between them depends on the expected conductivity and TDS of the samples to be measured.
