GreenClean Pond Block is a blend of beneficial bacteria and enzymes for natural pond balance, clarification, and maintenance. This product reduces excess nutrients in water bodies to improve water quality and clarity. Murky water, foul odors, and an increase in nutrient levels are often caused by the buildup of organic materials. Up to 5 acres of water can be treated by one block for 30-60 days. GreenClean Pond Blocks is recommended to be placed or suspended in areas where water movements or aeration occur to increase the dispersion of beneficial bacteria. Available in a box of 4 x 5 lb. blocks.