The Block™ by pond boss® PRO is a blend of live bacteria and enzymes specifically designed to improve water quality by reducing unwanted nutrients. Decaying nutrients such as leaves, grass clipping, dead plants, excess food and other organic material build at the bottom of the pond in what is commonly called the sludge layer of the pond. The sludge layer is most often responsible for undesirable odors and low oxygen levels. Regular use of pond boss® PRO The Block™ will degrade unwanted organic debris accumulation and improve the overall health of the pond while clearing the water column of unwanted organic material. This time released 5 lb block can treat up to 5 acre-ft of water over the course of 60 days.