AquaChek® Yellow Tests for Free Chlorine, Cyanuric Acid, pH and Total Alkalinity. 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. Its also a good idea to write down your results each time you test. Comes with complete instructions. 50 strips per bottle.
