CALDUR® Phosphate HR – Colorimetric
Phosphate determination in the water using a color chart (2.5-100 mg/l PO₄³-)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Phosphate HR – Colorimetric:
See also:
CALDUR® Phosphate HR Test Set – Colorimetric
Why is phosphate measured in the high range?
In many industrial and municipal applications, phosphate concentrations occur that far exceed the range of conventional test sets. Wastewater treatment plants, cooling water circuits and dosing systems require reliable control even in the range of 2.5 to 100 mg/l PO₄³-.
Phosphate is dosed as a corrosion inhibitor in cooling water systems. Typical target concentrations are 5-20 mg/l. Underdosing leads to corrosion, overdosing to unnecessary costs and deposits.
In sewage treatment plants, the phosphate concentration in the inlet is often 5-15 mg/l. Monitoring the effluent ensures that the legal limits are adhered to.
How does the test set work?
The CALDUR® Phosphate HR test set is based on the molybdate method. Phosphate reacts with the molybdate reagent to form a colored complex. The color intensity is proportional to the phosphate concentration.
The measured value is determined by direct color comparison with a 6-stage color chart supplied.
Advantages of the CALDUR® test set
- Measuring range 2.5 – 100 mg/l PO₄³-
Ideal for industrial applications and wastewater treatment plants
- 100 provisions per set
Economical for regular checks
- Quick analysis in just 1 minute
Immediate results without long waiting times
- Easy handling with only 1 reagent
No measuring devices required
- Robust plastic housing with hinged lid
Safe transportation and protection of reagents
Areas of application
Carrying out the measurement:
- Fill water sample into test tube up to the 10 ml mark
- Add 6 drops of reagent
- Close the test tubes and mix well
- Wait for 1 minute reaction time
- Perform color comparison with color chart
Tip for best results
For best results, the water sample should be clear and free of suspended solids.
If the water is cloudy, pre-filtration with a filter paper is recommended.
The response time of 1 minute should be observed.
Important notes
- Bring reagent to room temperature before use (20-25 °C)
- Adhere to response time
- Avoid direct sunlight during the measurement
- Rinse test tubes thoroughly with the sample before each measurement
- Use the phosphate LR test set for lower concentrations
Measuring range
| Measuring level | Description |
|---|---|
| 2.5 mg/l | Low concentration (weak blue) |
| 5 mg/l | Slightly increased concentration (light blue) |
| 10 mg/l | Average concentration (blue) |
| 25 mg/l | Increased concentration (strong blue) |
| 50 mg/l | High concentration (dark blue) |
| 100 mg/l | Very high concentration (deep blue) |
If the color is between two fields, you can form the average value
(e.g. between 10 and 25 mg/l = approx. 15-20 mg/l).
Number of possible provisions
You can carry out 100 measurements with one CALDUR® Phosphate HR test kit.
This refers to the amount of reagent contained.
Measuring accuracy and reproducibility
Readability: ± 1 color level
Reproducibility: Very good if the application instructions are followed
Interference: Silicate in high concentrations can influence the measured value. Highly colored or cloudy samples can make color readings more difficult.
What to do if measured values are out of range?
Measured value > 100 mg/l
| Dilution | Procedure | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml phosphate-free water | Measured value × 2 |
| 1:4 | 2 ml sample + 8 ml phosphate-free water | Measured value × 5 |
Measured value < 2.5 mg/l
For lower concentrations, use the CALDUR® Phosphate LR test set (0.25-10 mg/l PO₄³-).
Specifications at a glance
| Property | Value |
|---|---|
| Parameters | Phosphate (PO₄³-) |
| Item number | 31-072415 |
| Method | Colorimetric (molybdate) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | 2.5 to 100 mg/l PO₄³- |
| Color scale | 6 measuring levels (2.5 / 5 / 10 / 25 / 50 / 100 mg/l) |
| Analysis duration | 1 minute |
| Number of provisions | 100 |
| Number of reagents | 1 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 130 g |
| Scope of delivery |
|---|
| 1 reagent bottle (molybdate reagent) with detailed labeling |
| 1 test tube with 10 ml scale |
| 1 color card with 6 measuring levels |
| Detailed operating instructions (DE/EN) |
| Safety data sheets for all reagents |
| Robust hinged lid box (103 x 91 x 36 mm) |
Reagent details
| Reagent | Volume | Shelf life | Notes |
|---|---|---|---|
| Molybdate reagent | 30 ml | 24 months (24M) | Shake before use |
Shelf life: The shelf life starts from the date of manufacture (printed on the bottle).
After opening, the reagent should be used within 12 months.
Store the test kit in a dry, cool place (10-25 °C) and away from direct sunlight.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|---|
| Product category | Testset |
Flyer
Operating instructions
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