PondCare Pond Zyme with Barley Heavy Duty Pond CleanerAPI Pond Pond Zyme is a heavy duty pond cleaner, containing five specially selected bacterial strains in a stable dry form. Pond Zyme breaks down fish waste and dead algae that can cause cloudy water, sludge build up, and debris that clogs pumps and filters. Consumes pond sludge Powerful pond cleaner with natural bacteria and barley Reduces build up of fish waste Pond Zyme can be used in all ornamental koi ponds and water gardens, works in both cold