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Hanna Instruments Canada
Customer Support: (800) 842-6629

Total Hardness and pH Portable Photometer - HI96736

The HI96736 Total Hardness and pH Portable Photometer combines accuracy and ease of use in an ergonomic, portable design. A user can accurately determine these two parameters using ready made reagents. The HI96736 offers many advanced features including the exclusive CAL Check™ function used for performance verification and calibration of the meter.

CAL Check™ Validation and Calibration

Built-in Timer

Automatic Shut Off


The HI96736 portable photometer is for the measurement of total hardness and pH. Hanna’s portable photometers feature an advanced optical system; the combination of a special tungsten lamp, a narrow band interference filter, and silicon photodetector ensure accurate photometric readings every time. The Hanna exclusive CAL Check™ feature utilizes ready-made, NIST traceable standards to verify both meter validation and calibration. The exclusive cuvette locking system ensures that the cuvette is inserted into the measurement cell in the same position every time to maintain a consistent path length.

Features at-a-glance

CAL Check™ – Allows for performance verification and calibration of the meter using a CAL Check NIST traceable secondary standard.

GLP – Records the date of the last user calibration performed.

Built in timer – Allows the use of a timer to ensure the appropriate 3 minutes and 30 seconds reaction time is used for the chemical reaction. At the end of the timer countdown the meter will automatically take the reading. This feature ensures consistency across multiple users.

Indexing indent on meter – The meter has an indent that allows for a lock and key fit with the cuvette cap. This ensures that the cuvette is indexed consistently (same position) in order to maintain the same path length for accurate results.

Cooling Lamp Indicator – It is necessary to maintain a consistent temperature of the optical components in order to maintain a narrow wavelength band of light. This photometer has a cooling lamp indicator that is displayed for a short period of time before each measurement in order to allow the components to cool and obtain the highest accuracy possible.

Error messages – Messages on display alerting to problems including no cap, over range and under range readings, and light source error.

Auto-shut off – Automatic shut off after 10 minutes of non-use when the meter is in measurement mode. Prevents wastage of batteries in the event the meter is accidentally not turned off.

Battery status indicator

      The instrument has a battery level indicator to display reaming life as follows:

    • 3 lines for 100 % capacity
    • 2 lines for 66 % capacity
    • 1 line for 33 % capacity
    • Battery icon blinks when the capacity is less than 10 %.

    Units of measure – Appropriate unit of measure is displayed along with reading.

    photometer optical system

    The HI96736 measures two important water quality parameters: pH and total hardness. Total hardness refers to the presence of magnesium and calcium. Hardness from magnesium and calcium is due mainly to runoff water dissolving these salts as it flows or filters through different layers of strata. Hardness can also cause scaling of pipes in cooling and heating systems.

    The HI96736 offers two methods within one meter. pH determination uses the phenol red method; total hardness uses an adaptation of the Standard Methods for the Examination of Water and Wastewater, 18th Edition, colorimetric method.

    When the appropriate reagent is added to the sample, it will display a color change; the greater the concentration, the deeper the color. The associated color change is then colorimetrically analyzed according to the Beer-Lambert Law. This principle states that light is absorbed by a complementary color, and the emitted radiation is dependent upon concentration. For determination of pH and total hardness, a narrow band interference filter at 525 nm (green) allows only green light to be detected by the silicon photodetector and omits all other visible light emitted from the tungsten lamp. As the change in color of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases.

    cal check standards

    CAL Check™ standards with certificate

    The CAL Check™standards are used for calibration and performance verification of photometers with the CAL Check™ function. Individual sets of CAL Check™standards are available for the HI96736:

    • pH: HI96710-11
    • Total Hardness: HI96719-11

    Supplied with Certificate of Analysis

    • Lot number
    • Expiration date
    • Standard value @ 25℃
    • Reference meter NIST traceable

    Provided storage containers

    • Light tight
    • Protects from accidental breakage

Additional information

Weight 0.56 kg

Hardness, pH

pH Accuracy

±0.1 pH @ 25°C


SKU HI96736
Name Total Hardness and pH Portable Photometer – HI96736
pH Range 6.5 to 8.5 pH
pH Resolution 0.1 pH
pH Accuracy ±0.1 pH @ 25°C
pH Method Phenol red method. The reaction with reagents causes a red tint in the sample.
Hardness, Total Range 0.00 to 4.70 mg/L
Hardness, Total Resolution 0.01 mg/L
Hardness, Total Accuracy ±0.11 mg/L ±5% of reading @ 25°C
Hardness, Total Method Adaptation of the Standard Methods for the Examination of Water and Wastewater, 18th Edition, colo- rimetric method. The reaction between Mg/Ca and reagents causes a violet tint in the sample.
Photometer/Colorimeter Light Source Tungsten lamp
Photometer/Colorimeter Light Detector Silicon Photocell with narrow band interference filter @ 525 nm
Display Liquid Crystal Display (LCD)
Battery Type/Life 9V battery
Automatic Shut-Off after ten minutes of non-use in measurement mode; after one hour of non-use in calibration mode; with last reading reminder
Environment 0 to 50°C (32 to 122°F); RH max 95% non-condensing
Weight 360 g (12.7 oz.)
Dimensions 192x104x69mm (7.6×4.1×2.7”)

Ordering Info

HI96736 is supplied with two sample cuvettes with caps , 9V battery, instrument quality certificate, and instruction manual.


Total Hardness and pH Portable Photometer – HI96736