CALDUR® Aluminium – Colorimetric
Aluminum determination in water by color chart (0.05-2 mg/l Al)

Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Aluminium – Colorimetric:
See also:
CALDUR® Aluminum Test Set – Colorimetric
What is aluminum measured for?
Aluminum (Al) enters drinking water primarily via aluminum-based flocculants (e.g. aluminum sulfate, polyaluminum chloride). These agents are used in water treatment to remove impurities. The limit value for drinking water is 0.2 mg/l Al (Drinking Water Ordinance).
Elevated aluminum concentrations can lead to turbidity and are an indication of insufficient flocculation or filtration. In acidic waters (pH < 5), natural aluminum can be dissolved from the soil and reach concentrations that are toxic to fish.
Regular monitoring of the aluminum concentration is particularly important in waterworks, in industrial treatment and in environmental analysis.
How does the test set work?
The CALDUR® Aluminium Test Set – Colorimetric is based on a colorimetric color card method. After adding three reagents to the water sample, a characteristic coloration develops within 8 minutes, the intensity of which is proportional to the aluminum concentration.
The measured value is determined by direct color comparison with a supplied color chart.
Advantages of the CALDUR® test set
- Sensitive measuring range 0.05 – 2 mg/l Al
Covers the drinking water limit and above
- 150 provisions per set
Cost-efficient for continuous use in waterworks
- Easy handling with color card
Fast on-site determination without measuring devices
- Proven colorimetric method
Reliable and reproducible results
- Robust plastic housing with hinged lid
Safe transportation and protection of reagents
Areas of application
Carrying out the measurement:
- Fill water sample into test tubes up to the 10 ml mark
- Add 5 drops of reagent A and mix
- Add 5 drops of reagent B and mix
- Add 3 drops of reagent C and mix
- Wait for 8 minutes reaction time
- Perform color comparison with color chart
Tip for best results
The sample should have a pH value between 4 and 6, as aluminum is best detectable in this range. At higher pH values, aluminum can precipitate as hydroxide and is then not detected. Filter Truebe samples before measurement.
Important notes
- Adhere exactly to the response time of 8 minutes
- Avoid direct sunlight during the measurement
- Fluoride-containing samples can lead to lower results
- Reading may be more difficult with heavily colored samples
- Thoroughly rinse the test tube with the sample before each measurement
- Use glass appliances – aluminum can dissolve out of plastic
Measuring range
| Measuring level | Description |
|---|---|
| 0.05 mg/l | Very low concentration (pale pink) |
| 0.1 mg/l | Low concentration (light pink) |
| 0.2 mg/l | Drinking water limit value (pink) |
| 0.5 mg/l | Increased concentration (deep pink) |
| 1.0 mg/l | High concentration (pink-violet) |
| 2.0 mg/l | Very high concentration (violet) |
If the color lies between two fields, you can form the mean value
(e.g. between 0.1 and 0.2 mg/l = approx. 0.15 mg/l).
Number of possible destinations
With a CALDUR® aluminum test set you can carry out 150 measurements.
This refers to the quantity of reagents contained.
Measuring accuracy and reproducibility
Readability: ± 1 color level
Reproducibility: Very good if the application instructions are followed
Interference: Fluoride can interfere with the measurement as it forms stable complexes with aluminum. Iron(III) in high concentrations can also interfere. A photometric determination is recommended for heavily colored samples.
What to do if measured values are out of range?
Measured value > 2.0 mg/l
| Verduction | Execution | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml aluminum-free water | Measured value × 2 |
| 1:4 | 2 ml sample + 8 ml aluminum-free water | Measured value × 5 |
Measured value < 0.05 mg/l
The measured value is below the detection limit. This is a good result for drinking water, as the limit value of 0.2 mg/l is adhered to.
Specifications at a glance
Reagents (3 reagents)
| Property | Value |
|---|---|
| Parameters | Aluminum (Al) |
| Item number | 31-072200 |
| Method | Colorimetric (color chart) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | 0.05 to 2 mg/l Al |
| Color scale | 6 measuring levels (0.05 / 0.1 / 0.2 / 0.5 / 1.0 / 2.0 mg/l) |
| Duration of analysis | 8 minutes |
| Number of provisions | 150 |
| Number of reagents | 3 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 170 g |
| Scope of delivery |
|---|
| 3 reagent bottles (reagent A, reagent B, reagent C) 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 |
|---|---|---|---|
| Reagent A (buffer) | 30 ml | 24 months (24M) | Buffer solution, shake before use |
| Reagent B (color reagent) | 15 ml | 24 months (24M) | Color reagent, shake before use |
| Reagent C (compensation) | 10 ml | 24 months (24M) | Compensation reagent |
Shelf life: The shelf life starts from the date of manufacture (printed on the bottle).
After opening, the reagents should be used within 12 months.
Store the test kit in a dry, cool place (10-25°C) and protected from direct sunlight.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|---|
| Product category | Testset |
Flyer
Operating instructions
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