Automatic chemical dosing and water disinfection for pools
Automatic chemical dispensers make it significantly easier to keep the chemical values of the pool water stable. The recommended values are as follows:
- pH value: 7.2–7.4 (Note: there is a typo in the original text: 2-7,4)
- Free active chlorine (mg/l): 0.3–1.0
- Total alkalinity (mg/l): 80–120
- Total hardness (mg/l): 200–400
It is very important to put a dosing pump with the appropriate capacity into operation, knowing the volume of the pool water. Based on experience, dosing devices with the following capacities should be installed for the pool:
- Pool volume:
- 100 m3 water: 3 m3/h
- 500 m3 water: 5 m3/h
There are two main types of automatic chemical dispensers: analog or probe-controlled.
Analog dispensers dose without measurement, which can mostly be controlled by a timer. These devices are recommended for dosing hydrogen peroxide, algaecide, and flocculant, where dosing at a given volume rate and the introduction of a given amount of chemical into the pool water can be set on a daily or weekly basis.
For pH reduction, acid is recommended, and it is also recommended to add a disinfectant. The disinfectant is mostly chlorine or hydrogen peroxide.
The concentration of chemicals added to the pool water must be regulated, which is why only probe-controlled devices are suitable for this purpose. The placement of the probes is possible in a probe holder cell as well as installed directly into the pipeline of the filter circuit in an "in-line" manner. An advantage of probe holder cell systems is that they are equipped with a separate flow switch, which is why the chemical dosing device immediately enters a so-called "standby state" and stops dosing when the system shuts down. Depending on the method of dosing, we distinguish between diaphragm-piston and peristaltic chemical dispensers.
