AquaChek Silver 7-Way Pool and Spa Test Strips offer 7 important tests on a single strip. In less than a minute, you can see results for 7 key parameters including total hardness, total chlorine, total bromine, free chlorine, pH, total alkalinity, and cyanuric acid. The strips test faster and are easier to use than liquid dropper test kits. AquaCheck Silver offers enhanced colors for better readability. This set features an improved test for cyanuric acid (also called stabilizer). These strips allow you to test cyanuric acid up to 300 ppm (mg/L), a higher level than any available liquid kits. This cyanuric acid test works in pH between 7.0 and 8.4 and in Total Alkalinity at or below 240 ppm. For a clean, healthy, and happy pool, test twice a week with the AquaChek Silver Pool And Spa Test Strips.