Related Clues:

• Mr. Clean target
• Sargasso Sea floaters
• Worst of the population
• Fish tank buildup
• Growth on some ponds
• Pond scum and such
• Not a nice film?
• Tub buildup
• Pond surface growth
• Potential pond poisoner
• Ugly pond film
• Surface gunk
• Pool owner's concern
• Aquarium issue
• Film you don't want to see