The key to maintaining a crystal clear pool is a steady routine of sanitization. REGAL® sanitizers are designed to kill bacteria, algae and other living organisms. REGAL® sanitizers have built-in protection from the sun to maximize chlorine life. Strongest formula available. Built-in protection from the sun, extends the life of your sanitizers. Dissolves completely – Leaves no residue. Reduces the amount of acid required to keep your water balanced.