Haviland Durachlor Rust-N-ScaleThe Durachlor Rust N Scale works to prevent staining issues when metals are present in pool water. This granular product will help reduce the scale build up on pool surfaces and equipment. Not only will it protect the surfaces in your pool, but it is safe with all types of sanitizers. Prevents scale formation Targets iron, copper, manganese, and calcium hardness Safe with all types of surfaces, equipment, and sanitizing systems