Ball Valves and Sodium Hypochlorite: Sodium hypochlorite is inherently an unstable compound. As it decomposes, the resulting crystalline salts and oxygen gas can cause operational and safety issues with conventional ball valves. Hayward addresses these issues with the "Z-Ball" design. It effectively vents the gases while keeping the inner surfaces constantly wetted, ensuring problem free use. The "Z-Ball" valves are readily identifiable by the black handle and special label identifying the direction of the liquid flow. The hole is always positioned on the upstream side of the ball.