RISEPRO Chlorine Tester, pH & Cl2 Chlorine Level Tester Swimming Pool Water Spa Water Quality Analysis PC-102 CHLORINE CALIBRATION  Using your pool water to prepare 1.5ppm Chlorine solution. Then use this solution for calibration against the tester for first time only. No more calibration unless using in another pool! IF FAILURE OF CALIBRATION  If you failed to calibrate the tester against your 1.5ppm Chlorine solution. Please use traditional test strip to verify if it is 1.5ppm or not. Correct 1.5ppm Chlorine solution is a must for successful calibration! TEST CHLORINE & PH LEVEL  After a first time calibration, you can quickly find out your ideal range for both Chlorine and PH level for your pool water. If your CL/PH is beyond the ideal range, you can adjust your CL/PH by adding required ingredients to restore back to ideal range. FAST N SIMPLE METHOD  No more complicated and messy traditional liquid Chlorine and pH kit! RISEPRO&reg; Pool Tester can check the Chlorine and pH of your pool water in a fast and simple way after a simple calibration against Chlorine solution! FOR POOLS OR SPAS IN HOME SCALE  It serves as excellent DIY tool for any home scales pools or sps (NOT FOR SALTY WATER TYPE). Do not use for industrial or scientific purposes.