1. You all need to prepare 1.5 ppm chlorine solution, the purpose of your swimming pool water inspection2. If you are setting a chlorine level of 1.5 ppm or not (either uncertain or unable to find the calibration point), please use the traditional test strip3. Once your calibration is suitable for you, you do not need to re-calibrate unless you change the measurement pool to use a different pool water.A brief Risepro tester design, suitable for swimming pool or SPA family ratio (excluding salt lake swimming pool, industrial or scientific use)After the first successful calibration, you can test your pool water with chlorine and acid and alkali levels in a quick and easy way. Therefore, there is no need for any more complicated and chaotic "traditional liquid chlorine and acid-base set" With this practical tester, you can quickly test if your chlorine and PH values are in the ideal range of 7.8: chlorine 1.2 1.7 ppm and PH value 7.2 lied. If your test result is outside this range, let you have a piece of useful information, adapt to the corresponding pool of chlorine and acid and alkali. This is definitely a great tool, you may need to keep the pool water.specification:The recommended chlorine swimming pool and SPA grade are 1.2, 1.7 ppmRecommended PH swimming pool and SPA level are 7.2, 7.8Dimensions (CM)Host: 190 x 120 mmProbe with handle: 150 mm longProbe (only): 48 MM long (not included in the scope of supply black strap)Cable (only): 130 mm longPower supply: 1 AA 1.5 V alkaline batteryWeight: 160 g (without battery)Packing list:1*PH value1*Cl2 tester1*probe1* instruction manual