Monitoring Physicochemical Parameters of Pool Water Using Test Strips

A swimming pool is a complex hydraulic structure requiring qualified monitoring and maintenance. Basic analysis of the physicochemical parameters of pool water includes determining the hydrogen index (pH), hardness, alkalinity, and the concentration of disinfectants added to the water. Delta-CT LLC manufactures and sells test strips for monitoring the main physicochemical parameters of water, which are simple and quick to use, provide high analysis accuracy, and are priced lower than imported analogues.

The hydrogen index (abbreviated as pH) characterizes the acid-base balance of water. Monitoring and adjusting pH levels is crucial for several reasons. First, the bactericidal effect of disinfectants depends on pH levels. For example, chlorine-based disinfectants perform most effectively at a pH between 7.2 and 7.4. Second, if the pH is too low, the water becomes corrosive to the pool’s structural materials. Finally, water with extremely low or high pH levels can cause skin and eye irritation.

Adding disinfectants to pool water aims to eliminate pathogenic microorganisms, remove many impurities present in the water, and inhibit algae growth. Currently, chlorine-, bromine-, and active oxygen-based disinfectants are widely used. Since these substances are consumed in various chemical reactions, decompose under light, and evaporate, constant monitoring of disinfectant concentration in the water is necessary.

The total hardness of water is determined by the content of calcium and magnesium salts, primarily carbonates, bicarbonates, sulfates, and chlorides. If water hardness is below 40 mg/L (as CaCO₃), the water becomes corrosive to the pool’s structural materials (especially cement). Water with high hardness is harmful to the skin, clogging pores and leading to various skin conditions. The optimal range for total hardness in pool water is between 75 and 150 mg/L (as CaCO₃).

Another important physicochemical parameter of water is total alkalinity, which reflects the content of dissolved alkaline salts, primarily carbonates and bicarbonates. Low alkalinity can lead to pH fluctuations due to external factors. The higher the alkalinity, the more stable the pH remains when exposed to chemicals and disinfectants. If alkalinity exceeds 200 mg/L (as CaCO₃), this effect becomes so strong that it complicates manual pH adjustment. Therefore, the recommended total alkalinity range for pool water is between 80 and 140 mg/L (as CaCO₃).

To obtain reliable results when using test strips, follow these simple guidelines:
1. Strictly adhere to all instructions provided in the product manual for storage and use.
2. Store test strips in a cool, dry place, avoiding moisture and direct sunlight. Chemical vapors may affect test results, so keep the strips away from such exposure.
3. Remove only the necessary number of strips from the tube, and keep the tube closed.
4. Observe the specified immersion time for the test strips in the analyzed water.
5. Use the provided color scale only for the corresponding package of test strips.
6. Compare the color of the test strip with the reference scale under natural daylight. Sodium lamp lighting may distort color perception.
7. If the indicator zone’s color appears intermediate between two shades on the color scale, take the average value between the two closest reference points as the result.