Related Clues:
- Floor plants?
- Unwanted stuff in a fish tank
- Producers of oxygen
- Sample of the natural gases found in seaweed
- Unwelcome pool growth
- Pool film
- Kind of seaweed
- Growth in a neglected pool
- Nori or spirulina, e.g
- It helps turn a pond green
- Fish pond growth
- Fish food plant
- Red-tide contents
- Plant that lacks true roots and leaves
- Birdbath scum