Jack’s Magic The Emerald Stuff is a powerful 4-in-1 clarifier that will remove microscopic contaminants from your pool, giving it stunningly clear water with a jewel-like brilliance. Its formula helps prevent scaling, staining, scum lines and foaming by removing the contaminants that cause them, cutting the amount of maintenance you have to perform. Best of all, The Emerald Stuff is compatible with all types of sanitizer systems, making it a great choice for any pool.