SUITABLE FOR: The CL2 tester is suitable for swimming pool, spa, hot tub, etc. It is NOT recommended to immerse the probes in any liquid other than pool or spa water. Recommended chlorine level for pool and spa: 1.2 to 1.7 ppm and 7.2 to 7.8 ph for pH level for swimming pool and spa. EASY TO USE: The chlorine tester is simply to immerse the electrode of the pH meter in the solution and press the button to measure. Portable design, easy and comfortable to use. High precision design, with dial plate, easy to read. HIGH QUALITY: The spa chlorine tester is made of premium plastic shell, which is durable and sturdy. Specially designed for family swimming pools PRACTICAL TOL: A handy tool for testing water pH and chlorine level for swimming pool and spa. Easy to use, you can quickly test if the chlorine and PH are within the ideal range. Note: The detector will not recommend submersion in water other than pool water or spa.