Having your own pool is the dream come true of all water rats. For carefree splashing in the cool water, the pool must be regularly maintained and the water quality checked. The pH value is of enormous importance for the quality of the pool water. If the ph value is incorrect, there is a risk of eye irritation, skin irritation and damage to the pool in the worst case scenario. We tell you how you can easily measure the ph-value of your swimming pool at home and which possibilities there are to correct the value.
What is the ph-value
The ph-value indicates whether an aqueous solution is acidic or basic. Ph stands for pondus hydrogenii or potentia hydrogenii, which means weight or. Power of hydrogen. the ph value thus describes the concentration or the activity of hydrogen ions in an aqueous solution.
The following applies: the lower the value, the more acidic the solution and the higher the value, the more alkaline it is. the ph scale ranges from 0 to 14. Values< 7 are considered acidic, values> 7 as alkaline. 7 is neutral, i.e. the ideal value for your pool water.
Examples from our everyday life to help you understand the different ph values a little better:
Ph-value scale
| stomach acid | 1,5 |
Optimum ph value in the pool
The ph-value of your pool water is influenced by several factors. This includes:
- The water temperature
- The frequency of bathing and use of the pool
- The degree of contamination of the pool water
- Rain
- the hardness of the water you use to fill the pool
- The addition of disinfectants and flocculants
Therefore, if the pool is used frequently during the summer months and is polluted, for example, by sunscreen or leaves and grass, then the water quality should be checked at least twice a week and the ph value should be adjusted if necessary.
The ideal pH value of the pool water should be between 7 and 7.5. In the following section you will learn what happens if this value is exceeded or undershot.
The ph-value is too low
If the ph-value is below 7, the pool water is too acidic. Skin, mucous membrane and eye irritation can occur. In addition, metal pool parts can be damaged by corrosion and pool materials and other parts such as filters can be attacked. An unpleasant odor can also indicate that the pH value is too low. Here you should act quickly and raise the pH value. You can find out exactly how this works in the section on setting the ph value.
The ph-value is too high
If the ph is too high, the effectiveness of other pool chemicals such as chlorine to disinfect the water may be reduced. If chlorine loses its effectiveness, it smells unpleasantly of the chemical. A milky cloudiness of the water due to a high lime content and the formation of algae can also indicate that the pH value is too high. If the pH value is too high, irritation of the eyes and skin can also occur. If the ph-value is too high, it can be regulated with special ph-value lowers.
Ph-value measurement
The ph value is measured using the so-called ph scale and read off from the color scale. Here, a ph indicator indicates the respective value: indicator substances (so called. Acid-base indicators) such as thymol blue or phenolphthalein react to the liquid to be tested and change color depending on the pH value. In acidic solutions, the ph indicator turns red. Alkaline solutions, on the other hand, are indicated by the blue color of the ph indicator.
To measure the ph-value of your pool water, you can choose between different measuring methods and applications. We have summarized the most common methods for you. A distinction is made between analog and digital measurement:
- Analog measurement – ideal for smaller pools and construction pools
Test strips are probably the easiest method to determine the pH value of your pool water. The test strips are sealed with indicator substances and are simply held in the pool water. Depending on the ph value, the strip changes color and the value can be read off from the color scale provided. The disadvantage of measuring with test strips, however, is that it is rather inaccurate. However, it helps to get an approximate tendency whether your water is too acidic or too alkaline and the ph-value needs to be readjusted.
When using the test kits, be sure to follow the manufacturer’s instructions. However, such test kits are similar in their application: water is filled into the supplied test tube and a few drops of the test liquid (indicator solution) are dripped into it. Close the cap and shake the tube. Now the water changes color. The ph value can be read off the scale by means of the color.
These test kits work similarly to those with test liquid. Here, however, a test box is dipped into the pool water and a tablet from the blister pack is pressed into the box. If the box has a lid, then the lid is closed and the box is shaken. If the tablet does not have a lid, crush it until it dissolves. Now you can read the ph value from the table.
With this method, the value is determined electrochemically. The most common application of the ph-meter is the measurement through glass electrodes of a so-called single-rod measuring chain. This combines a glass electrode and a so-called reference electrode. The latter is usually a silver-silver chloride half-cell, i.e. a specific type of electrode. Immerse the ph meter in the liquid to be measured. A half-cell reaction now takes place at the glass membrane and an electrical potential is formed. This potential is directly related to the concentration of hydrogen. The ph value can then be determined from the potential difference to the reference electrode.
In newer ph meters, field-effect transistors are used. Transistors are immersed in the solution. Hydrogen ions are deposited. An electrical potential is built up, which in turn can be meas.
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Digital meters
The advantage is that digital meters calibrate automatically and are very easy to use: simply hold the meter in the water and the value is displayed. Often, other values such as the chlorine content can also be determined with such digital measuring instruments. another advantage: digital measuring instruments can determine the ph value very accurately.
please note: always follow the manufacturer’s specifications and operating instructions. Each test method must be applied correctly in order to make a reliable statement about the pH value of your pool water.