Wide application: This pH meter is suitable for swimming pools, tap water, home brewing, laboratory testing, aquarium maintenance and more. It tests pH and chlorine (Cl2) levels in water, and is used to routinely monitor the pH and chlorine content of swimming pools, spas and various water sources. Practical and reliable: For pools and spas, chlorine content is recommended in the range 1.2–1.7 ppm and pH 7.2–7.8. The digital water quality monitor reads pH and chlorine quickly and accurately, helping ensure pool and spa water is safe, comfortable and properly balanced. Portable and convenient: Hand-held pen type with a compact form that fits in a pocket or bag. Built-in automatic temperature compensation (ATC) eliminates the need to measure temperature separately, allowing accurate pH readings from 0 C to 80 C (32 F to 176 F). Fast and precise: Provides rapid results without color charts or test strips. Resolution 0.01, accuracy 0.05, with full pH measurement from 0 to 14. Factory-calibrated. Safe measurement ranges: chlorine 1.2–1.7 ppm, pH 7.2–7.8.