HI97725 is an advanced portable photometer for the measurement of chlorine, cyanuric acid, and pH in water. This meter offers a superior optical system that utilizes a reference detector and narrow band interference filters for extremely fast and repeatable measurements.
The HI97725 meter measures four important parameters in the treatment and disinfection of swimming pools, spas and cooling towers. HI97725 measures free and total chlorine, pH and cyanuric acid. Each plays a very important role in the treatment of water.
Chlorine is a commonly used for its disinfection properties. The effectiveness of the free chlorine is pH dependent. As pH decreases less than 7.4 the chlorine is found as hypochlorous acid and when pH increases above 7.4, chlorine is predominantly in the hypochlorite ion form. Hypochlorous acid is 100X more effective at killing bacteria than hypochlorite. The chlorine method is an adaptation of the US EPA Method 330.5, DPD Colorimetric Method while the pH is an adaptation of the Phenol Red Method. For chlorine and pH, when the appropriate reagent is added to the sample, is a color change will occur. The greater the concentration, the deeper the color.
Up to 90% of the chlorine can be broken down by sunlight in a matter of hours. Adding cyanuric acid to the water stabilizes the chlorine which will slow down the breakdown process. The cyanuric acid is measured by a turbidimetric method. For cyanuric acid the cloudiness of the sample is dependent on the concentration. The associated color/turbidity change is 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 all four parameters, a narrow band interference filter at 525 nm allows only green light to be detected by the silicon photodetector and omits all other visible light emitted from the LED lamp. As the change in color/turbidity of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases.
CAL Check
Advanced features including CAL-Check to verify performance and if necessary, recalibrate.
Setup Options
Backlit dot matrix LCD that offers an exceptionally intuitive user interface that is easy to read and understand.
Tutorial Mode
Tutorial mode for step-by-step instructions to guide a first-time user in how to perform a measurement correctly.
Reaction Timer
Built-in reaction timer that ensures consistency amongst multiple users.
Stable Light Source:
High Efficiency Light Source:
High Quality Filters:
Greater Light Yield:
A focusing lens collects all of the light that exits the cuvette, eliminating errors from imperfections and scratches that may be present in the glass. The use of the convex lens reduces the need for indexing cuvettes.
CAL Check Functionality:
Large Cuvette Size:
Intuitive Dot Matrix Display:
Auto-off Protection:
| SKU | HI97725-web |
|---|---|
| Product Name | Chlorine, Cyanuric Acid, and pH Portable Photometer with CAL Check – HI97725 |
| Quote Required | Yes |
| pH Range | 6.5 to 8.5 pH |
| pH Resolution | 0.1 pH |
| pH Accuracy | ±0.1 pH of reading at 25°C |
| pH Method | adaptation of the Phenol Red Method |
| Free Chlorine Range | 0.00 to 5.00 mg/L (as Cl2) |
| Free Chlorine Resolution | 0.01 mg/L |
| Free Chlorine Accuracy | ±0.03 mg/L ±3% of reading at 25°C |
| Total Chlorine Range | 0.00 to 5.00 mg/L (as Cl2) |
| Total Chlorine Resolution | 0.01 mg/L |
| Total Chlorine Accuracy | ±0.03 mg/L ±3% of reading at 25°C |
| Chlorine Method | adaptation of US EPA Method 330.5, DPD Colorimetric Method |
| Cyanuric Acid Range | 0 to 80 mg/L (as CYA) |
| Cyanuric Acid Resolution | 1 mg/L |
| Cyanuric Acid Accuracy | ±1 mg/L ±15% of reading at 25°C |
| Cyanuric Acid Method | adaptation of the Turbidimetric Method |
| Photometer/Colorimeter Light Source | LED with 525 nm bandpass filter |
| Photometer/Colorimeter Light Detector | silicon photocell |
| Bandpass Filter Bandwidth | 8 nm |
| Bandpass Filter Wavelength Accuracy | ±1.0 nm |
| Cuvette Type | round 24.6 mm diameter (22 mm inside) |
| GLP | yes |
| Display | 128 x 64 pixel B/W LCD with backlight |
| Logging Memory | 50 readings |
| Battery Type/Life | 1.5 V AA Alkaline (3 pcs.) / > 800 measurements (without backlight) |
| Automatic Shut-Off | after 15 minutes of inactivity (30 minutes before a READ measurement) |
| Environment | 0 to 50°C (32 to 122°F); 0 to 100% RH (IP67) |
| Weight | 380 g (13.4 oz.) |
| Dimensions | 142.5 x 102.5 x 50.5 mm (5.6 x 4.0 x 2.0'') |
| Ordering Information | HI97725C is supplied with CAL Check standards, cuvettes (2), caps (2), plastic inserts for cuvette, (2), scissors, cuvette cleaning cloth, 1.5V AA batteries (3), instruction manual, and instrument quality certificate, packaged in a rugged, thermoformed carrying case. |
