Instructions for use:
Immerse the test tube into the pool water to a depth of 20–50 cm, fill it to the marked level and remove it from the water.
Add 4 drops of Orthotolidine reagent into the tube labeled “Cl”, and 4 drops of Phenol Red reagent into the tube labeled “pH”.
Close the tube and shake gently.
After 10–15 seconds, the actual Cl and pH levels will appear on the color scale.
Use appropriate chemical products to adjust the water parameters to pH = 7.2–7.6 and Cl = 0.3–0.6.