Contaminants cloud the water of garden ponds and destroy their delicate biological balance. This poses a serious health risk to fish, and may even kill some fish. use Use TetraPond Water Clarifier to keep your water clean and clear by safely clumping contaminants into removable masses which sink to the pond's bottom. For best results, remove the clumps using the pond filter, wet vacuum, or skimming net to keep pond water clear and safe. 8.45 oz size treats up to 1,250 gallons.