The Valterra Blue Devil #5 Solution is a 1/2-ounce reagent refill designed for use with Blue Devil Test Kits to measure total alkalinity levels in swimming pools and spas. Regular monitoring of total alkalinity is essential for maintaining balanced water chemistry, which ensures both bather comfort and the longevity of pool equipment. To use, follow your test kit's instructions by adding the #5 Solution to your water sample and observing the resulting changes to determine the necessary chemical adjustments. This solution is compatible with existing Blue Devil Test Kits.