Fill a bucket or sink with hot water.
Add ¼ cup of salt for each gallon of water. Put the rocks in the container, and let them soak for 30 minutes.
Take the rocks out of the bucket, and rinse them under warm running water. Rinse for a minimum of one minute to ensure that all traces of salt are washed away. Residual salt may affect the pH level of aquarium water.
Scrub the rocks with a stiff-bristle nylon brush. Using clean water, rinse any remaining algae off the rocks.
Return the rocks to your aquarium.
Things You Will Need
- Bucket -- optional
- Hot water
- Stiff-bristle brush
- If the rocks are along the edge of a pond, pour hot water over them and scrub them with a stiff-bristle metal brush. The algae should be easy to remove.