The HI96745 portable photometer is for the measurement of pH, free and total chlorine, total hardness, and low range iron. 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 – Ensures the appropriate reaction time is used for the chemical reaction. At the end of the timer 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 remaining 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.

Chlorine and pH are two of the most closely monitored parameters in the analysis of water quality. The disinfecting power of a chlorine solution is pH-dependent; hypochlorous acid (HOCl) is the more effective form of chlorine that is predominant at lower pH levels. As the pH increases, the less effective hypochlorite (OCl-) form becomes more prevalent. Hardness is also an important water quality parameter as it can indicates the presence of magnesium and calcium, which are responsible for scaling of pipes in heating and cooling systems. In domestic water, iron can cause an unpleasant taste, stain laundry, or damage kitchenware; it is also an indicator of ongoing corrosion in piping systems.

The HI96745 offers multiple methods within one meter. pH determination uses the phenol red method; free and total chlorine determination uses an adaptation the Standard Method 4500-Cl G; total hardness determination uses an adaptation of the Standard Methods for the Examination of Water and Wastewater, 18th Edition, colorimetric method; low range iron determination uses an adaptation of the TPTZ method. The reagents are in powder or liquid form depending on the parameter being tested.

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, free and total chlorine, total hardness, and iron, 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 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 HI96745:

• pH: HI96710-11
• Free Chlorine: HI96701-11
• Total Chlorine: HI96711-11
• Total Hardness: HI96719-11
• Iron: HI96746-11

Supplied with Certificate of Analysis

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

Provided storage containers

• Light tight
• Protects from accidental breakage