Kasco Marine Macro-Zyme Pond Bacteria is the green approach to reducing and reversing the seasonal buildup of sludge in ponds and the associated nutrient levels and odors. Macrozyme bacteria eat the grass clippings, leaves, animal waste and fertilizer and lawn chemicals that accumulates as organic sludge on the bottom of your ponds. This reduces nutrient loads and odors and improves water clarity. U.S.A.