Related Clues:

• Pool-owner's problem
• Pool growths
• Phycologist's study
• Microscopic pond organism
• Bit of marine life
• Aquatic plants
• Organism that can be brown, red or green
• Pond problem
• Tank top?
• Snails' snack
• Fishtank growth
• Bit of scum
• Marine flora
• Part of a pond problem
• Aquatic organisms