Caldur® pH 5-8 – Colorimetric
pH determination in the neutral range using a color chart (pH 5-8)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for Caldur® pH 5-8 – Colorimetric:
See also:
CALDUR® pH 5-8 test set – Colorimetric
What is the pH value 5-8 measured for?
The pH range 5-8 is the most important range for drinking water and most natural waters. Drinking water typically has a pH value between 6.5 and 8.5, with the optimum range being pH 7.0-7.5.
The pH value influences numerous water treatment processes: the effectiveness of disinfectants, the solubility of metals, the efficiency of flocculants and the water’s tendency to corrode. Even small pH changes can have a considerable effect on water quality.
In aquaristics, the pH value is crucial for the well-being of fish and plants. Most freshwater fish prefer a pH value between 6.5 and 7.5.
How does the test set work?
The CALDUR® pH 5-8 Test Set – Colorimetric uses a mixing indicator that takes on a characteristic color depending on the pH value of the sample. After adding a reagent to the water sample, the color is compared with the color chart provided within 1 minute.
Advantages of the CALDUR® test set
- Optimized for the neutral pH range 5-8
Higher resolution than universal pH test sets in the practical range
- 300 provisions per set
Very economical for continuous use
- Fastest analysis in just 1 minute
Immediate results on site
- Only 1 reagent required
Particularly quick and easy handling
- 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 mixing indicator and mix
- Wait 1 minute
- Perform color comparison with color chart
Tip for best results
The sample should have a temperature between 15 and 25°C, as the pH value is temperature-dependent. With samples containing CO₂ (e.g. groundwater), the pH value can increase due to outgassing – therefore measure as quickly as possible after sampling.
Important notes
- Measure sample as soon as possible after collection
- Heavily colored samples can make reading difficult
- High chlorine concentrations can affect the Reagent
- Thoroughly rinse the test tube with the sample before each measurement
- Perform color comparison in daylight
Measuring range
| Measuring level | Description |
|---|---|
| pH 5.0 | Acidic (yellow) |
| pH 5.5 | Slightly acidic (yellow-green) |
| pH 6.0 | Slightly acidic (light green) |
| pH 6.5 | Almost neutral (green) |
| pH 7.0 | Neutral (green-blue) |
| pH 8.0 | Slightly alkaline (blue) |
If the color lies between two fields, you can form the mean value
(e.g. between pH 6.5 and 7.0 = approx. pH 6.7-6.8).
Number of possible destinations
With a CALDUR® test set pH 5-8 you can carry out 300 measurements.
This refers to the quantity of reagents contained.
Measuring accuracy and reproducibility
Readability: ± 0.5 pH units
Reproducibility: Very good if the application instructions are followed
Interference: Heavily colored or true samples can make color readings difficult. At very high salt concentrations, the Reagent may deviate slightly. Chlorine in high concentrations can influence the Reagent.
What to do if measured values are out of range?
Measured value > pH 8
Use the CALDUR® pH 8-12 test set for the alkaline range.
Measured value < pH 5
Use the CALDUR® pH 2-5 test set for the acidic range.
Specifications at a glance
Reagents (1 reagent)
| Property | Value |
|---|---|
| Parameters | pH value (neutral) |
| Item number | 31-072385 |
| Method | Colorimetric (mixing indicator) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | pH 5 to 8 |
| Color scale | 6 measuring levels (5.0 / 5.5 / 6.0 / 6.5 / 7.0 / 8.0) |
| Analysis duration | 1 minute |
| Number of provisions | 300 |
| Number of reagents | 1 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 120 g |
| Scope of delivery |
|---|
| 1 reagent bottle (mixing indicator) 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 |
|---|---|---|---|
| Mixing indicator (pH 5-8) | 30 ml | 24 months (24M) | Indicator solution, shake 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 protected from direct sunlight.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|
Flyer
Operating instructions
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