The Valterra Blue Devil Cyanuric Acid Test is an 8-ounce reagent refill designed for use with Blue Devil Test Kits to measure cyanuric acid levels in swimming pools and spas. Monitoring cyanuric acid is essential for maintaining water quality, as it helps stabilize chlorine levels, ensuring effective sanitation. To use, follow your test kit's instructions by adding the reagent to your water sample and observing the results to determine if adjustments are necessary. This solution is compatible with existing Blue Devil Test Kits.