The DPD “N” tester is used to measure the free (active) chlorine and the pH value of pool water. It works on the principle of visual comparison of the coloured water with a colour chart next to the sampling chambers – after adding the chlorine/pH tablets the water changes colour and the relevant values are adjusted according to the result.
If the values are not within the standard (pH 6.9–7.4; Cl 0.3–0.7), adjust them with pool chemicals. Always adjust the pH first and only then the chlorine. Only increase the chlorine – do not lower an excessively high value, it will drop on its own within a few days. Chlorine is applied only after adjusting the pH, because outside the recommended values its effectiveness drops rapidly.
Technical parameters
- Measured parameters: free chlorine and pH
- Principle: DPD tablet method with a colour chart
- Version: Lovibond, orange colour
- Recommended values: pH 6.9–7.4; Cl 0.3–0.7
