CALDUR® Ammonium – Colorimetric
Determination of ammonium in water using a color chart (0.1-10 mg/l NH₄⁺)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Ammonium – Colorimetric:
See also:
CALDUR® Ammonium Test Set – Colorimetric
What is ammonium measured for?
Ammonium (NH₄⁺) is an important Reagent for water quality and is produced by microbial decomposition of organic material or enters the water through fertilizers, wastewater and agricultural inputs. An increased ammonium concentration can indicate contamination and must be monitored critically, especially in drinking water, aquariums and fish farms.
The limit value for drinking water in Germany is 0.5 mg/l NH₄⁺ (Drinking Water Ordinance). In bodies of water, ammonium serves as a nutrient for algae and plants, whereby increased concentrations can lead to eutrophication. Ammonium is toxic to fish – even small amounts can cause gill damage.
Ammonium control is essential in aquariums, as ammonium is first broken down by bacteria to nitrite and then to nitrate in the biological balance of the aquarium. Regular measurement protects fish from poisoning and provides information on the functionality of the biofilter.
How does the test set work?
The CALDUR® Ammonium Test Set – Colorimetric is based on the indophenol blue method. After adding three reagents to the water sample, a characteristic blue-green coloration develops within 8 minutes, the intensity of which is proportional to the ammonium concentration.
The measured value is determined by direct color comparison with a supplied 6-stage color chart. The method is highly specific for ammonium and exhibits only minor cross-reactions with other nitrogen compounds.
Advantages of the CALDUR® test set
- Quick analysis in just 8 minutes
Ideal for regular checks in aquariums, fish ponds and sewage treatment plants – immediate results
- Wide measuring range from 0.1 to 10 mg/l NH₄⁺
Covers the entire practical range from drinking water to waste water
- 100 provisions per set – economical in continuous use
Cost-efficient for daily checks in aquaculture, waterworks and environmental analysis
- Colorimetric use with color chart
Easy handling without additional devices – perfect for mobile applications
- Highly specific method without interference
Precise measurement results even with complex water matrices
- Robust, waterproof plastic housing with hinged lid
Safe transportation and protection of reagents – durable and reliable
Areas of application
Carrying out the measurement:
- Fill water sample into test tube up to the 10 ml mark
- Add 3 drops of reagent A and mix
- Add 3 drops of reagent B and mix
- Add 1 dosing spoon of reagent C, shake well until completely dissolved
- Wait for 8 minutes reaction time (coloration develops)
- Evaluation by 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 (e.g. Whatman No. 1) is recommended.
The reaction time of 8 minutes should be strictly adhered to, as the color intensity is time-dependent.
⚠️ Important notes
- Bring reagents to room temperature before use (20-25°C)
- Precisely adhere to the response time of 8 minutes for precise measurement results
- Avoid direct sunlight during the measurement
- Rinse test tubes thoroughly with distilled water after use
- Chlorine in the water can interfere with the measurement – reduce with thiosulphate if necessary
Measuring range
| Measuring level | Description |
|---|---|
| 0.1 mg/l | Very low concentration (light yellow-green) |
| 0.25 mg/l | Low concentration (greenish) |
| 0.5 mg/l | Increased concentration (green) |
| 1.0 mg/l | Average concentration (blue-green) |
| 5.0 mg/l | High concentration (blue) |
| 10.0 mg/l | Very high concentration (dark blue) |
If the color is between two fields, you can form the mean value
(e.g. between 0.5 and 1.0 mg/l = approx. 0.7-0.8 mg/l).
Number of possible provisions
You can carry out 100 measurements with one CALDUR® Ammonium test set.
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
Interferences: Turbidity and coloration of the sample can influence the result (filter the sample if necessary). High calcium concentrations (> 500 mg/l) can lead to slight deviations.
What to do if measured values are out of range?
Measured value > 10 mg/l
| Dilution | Procedure | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml distilled water | Measured value × 2 |
| 1:4 | 2 ml sample + 8 ml distilled water | Measured value × 5 |
| 1:9 | 1 ml sample + 9 ml distilled water | Measured value × 10 |
Measured value < 0.1 mg/l
Measured value is below the detection limit. This is generally not critical and indicates
that the ammonium concentration is very low (water is harmless with regard to ammonium).
Specifications at a glance
Reagents (reagent A, B, C)
| Property | Value |
|---|---|
| Parameters | Ammonium (NH₄⁺) |
| Item number | 31-072210 |
| Method | Colorimetric (indophenol blue) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | 0.1 to 10 mg/l NH₄⁺ |
| Color scale | 6 measuring levels (0.1 / 0.25 / 0.5 / 1.0 / 5.0 / 10.0 mg/l) |
| Duration of analysis | 8 minutes |
| Number of provisions | 100 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 180 g |
| Scope of delivery |
|---|
| 3 reagent bottles (reagent A, B, 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 | 10 ml | 36 months (36M) | Shake before use |
| Reagent B | 10 ml | 36 months (36M) | Shake before use |
| Reagent C | 5 g (powder) | 36 months (36M) | Store in a dry place, dissolve before use |
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 away from direct sunlight.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|---|
| Product category | Testset |
Flyer
Operating instructions
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