What is sodium nitrate used for in ponds?

• A. Source of chlorine
• B. Source of oxygen for microbes
• C. Nutrient for algae
• D. pH adjuster

Answer: (B)

Sodium nitrate delivers nitrogen to the pond as nitrate, which is a crucial nutrient that algae and many microbes need to grow. It does not supply oxygen; oxygen in ponds comes from photosynthesis by aquatic plants and algae or from aeration. So the role of sodium nitrate is to act as a nutrient source (nitrogen) for aquatic organisms, which can boost growth but must be managed to avoid eutrophication.