
Private customers can also find our range in our partner store Ampha-Analyse.
Carbonate hardness (temporary hardness) is an important parameter in water chemistry and provides information about the concentration of hydrogen carbonate and carbonate ions in the water. It is part of the total hardness and plays a decisive role in the buffering capacity of the water (pH stability).
Monitoring carbonate hardness is essential in boiler systems, as carbonate hardness precipitates and forms scale when heated. This impairs heat transfer and can lead to serious damage to the system. The carbonate hardness in boiler water should be as low as possible (< 0.5 °dH). In aquariums, carbonate hardness stabilizes the pH value and prevents dangerous pH fluctuations. A carbonate hardness of 3-10 °dH is optimal for most fish. Carbonate hardness also plays an important role for water quality in drinking water treatment and pool water.
The CALDUR® Carbonate hardness CH test set works according to the proven acid-base titration method. The hydrogen carbonate is neutralized by adding an acid solution drop by drop to a water sample with Reagent. The color changes at the equivalence point – the number of drops used corresponds directly to the carbonate hardness.
The method is simple, fast and provides reliable results in the measuring range from 0 to 20 °dH with a resolution of 1.0 °dH (0.5 °dH with half the sample quantity).
Ideal for daily checks in boiler systems and aquariums – immediate results
Covers all practice-relevant ranges, optional 0.5 °dH resolution possible
Cost-efficient for regular inspections in waterworks and industrial plants
No additional devices required – direct reading
Clearly recognizable end point of the titration
Choice between hinged lid box and folding box
For best results, the water sample should be clear and free of suspended solids.
The color change from green to red/orange is clearly visible.
Shake well after each drop to ensure a complete reaction.
| Measured value per drop | Sample quantity | Measuring range |
|---|---|---|
| 1.0 °dH | 10 ml | 0 to 20 °dH |
| 0.5 °dH | 20 ml | 0 to 10 °dH (higher resolution) |
With a CALDUR® Carbonate hardness CH test set you can carry out 100 measurements at 10 °dH.
With lower hardnesses, more measurements are possible.
Resolution: 1.0 °dH (with 10 ml sample) or 0.5 °dH (with 20 ml sample)
Reproducibility: Very good if performed carefully
Interferences: No significant interferences for typical water samples
| Dilution | Procedure | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml distilled water | Number of drops × 2 = °dH |
| 1:4 | 2 ml sample + 8 ml distilled water | Number of drops × 5 = °dH |
| Property | Value |
|---|---|
| Parameters | Carbonate hardness (CH) |
| Item number | 31-071420 |
| Method | Acid-base titration |
| Measuring principle | Droplet titration with color change |
| Measuring range | 0 to 20 °dH |
| Resolution | 1.0 °dH or 0.5 °dH |
| Analysis duration | 1 minute |
| Number of determinations | 100 at 10 °dH |
| Packaging | Hinged lid box or folding box |
| weight | approx. 120 g |
| Scope of delivery |
|---|
| 1 titration solution (30 ml) |
| 1 test tube with 10 ml / 20 ml scale |
| Detailed operating instructions (DE/EN) |
| Safety data sheets |
| Hinged lid box or folding box |
| Reagent | Volume | Shelf life | Notes |
|---|---|---|---|
| Titration solution | 30 ml | 24 months (24M) | Shake before use, already contains Reagent |
Shelf life: The shelf life starts from the date of manufacture (printed on the bottle).
After opening, the titration solution should be used within 12 months.
Store the test set in a dry, cool place (10-25°C) and away from direct sunlight.
| Packaging | Folding box, Hinged lid box |
|---|


