Pond Sludge Reducer Block - 4 pk

These bio-active cleaning blocks keep water clean and clear by breaking down wastes which accumulate on the bottom of ponds as a sludge layer. Also great to use during the setup of a new pond and the spring start-up or fall shut-down of established ponds. The blend of safe enzyme producing bacteria helps develop and maintain the pond's natural biological balance. 4 blocks treat up to 1,000 gallons.