Check the listing for details. AquaChek 511244A 4-IN-1 Chlorine Swimming Pool and Spa Test Strips- 50 Pack. Condition: New. Listed at 12.96 USD. AquaChek 511244A 4-IN-1 Chlorine Swimming Pool and Spa Test Strips - 50 Pack Item Number: 107790 AquaChek® Yellow test strips - allow pool and spa owners to test their chlorine-based sanitation systems for free chlorine, cyanuric acid, pH, and total alkalinity. Simply insert the test strip into the pool or spa water for 1 second, and several seconds later you have fast, accurate results. It is recommended that you test your pool a minimum of twice per week, and spas before each use, to get an accurate picture of the health of your system. To keep you pool water clean and healthy, test the water at two ends or sides of the pool a minimum of twice a week! If used in a spa we recommend testing it before and after each use. It’s also a good idea to write down your results each time you test. Tests for: Free Chlorine, pH, Total Alkalinity, Cyanuric Acid (Stabilizer) Get 4 important test results in just one dip! Just dip an AquaChek Yellow strip in your pool or spa water for one second and remove it immediately. You get test results in seconds! To keep your pool at its best, test at each end a minimum of twice a week, and test your spa before each use. It’s also a good idea to write down your results each time you test. Directions to Use: Dip and remove strip. Wait 15 seconds. Compare pads to color chart on bottle.AquaChek 511244A 4-IN-1 Chlorine Swimming Pool and Spa Test Strips - 50 Pack Item Number: 107790 AquaChek® Yellow test strips - allow pool and spa owners to test their chlorine-based sanitation systems for free chlorine, cyanuric acid, pH, and total alkalinity. Simply insert the test strip into the pool or spa water for 1 second, and several seconds later you have fast, accurate results. It is recommended that you test your pool a minimum of twice per week, and spas before each use, to get an accurate picture of the health of your system. To keep you pool water clean and healthy, test the water at two ends or sides of the pool a minimum of twice a week! If used in a spa we recommend testing it before and after each use. It’s also a good idea to write down your results each time you test. Tests for: Free Chlorine, pH, Total Alkalinity, Cyanuric Acid (Stabilizer) Get 4 important test results in just one dip! Just dip an AquaChek Yellow strip in your pool or spa water for one second and remove it immediately. You get test results in seconds! To keep your pool at its best, test at each end a minimum of twice a week, and test your spa before each use. It’s also a good idea to write down your results each time you test. Directions to Use: Dip and remove strip. Wait 15 seconds. Compare pads to color chart on bottle.