Aquachek Chlorine Test Strips 50 Count For Pools And Spas Performs 4 Tests In 1 Dip, Free Chlorine, pH (Acidity), Alkalinity (Ph Buffer), Cyanuric Acid (Uv / Sun Block) Yellow Series Test Strips By Hach 511242A Item #: AQC-45-879 Mfg #: 511244A UPC Code: 090944012429