How to Clean Algae Off of Rocks in a Fish Tank

Rocks provide attractive decor to a fish tank, as well as hiding places for your tank's inhabitants. They can be purchased from pet or aquarium supply stores and come in a variety of sizes and colors. However, adding rocks to a tank requires regular cleaning to remove algae that accumulates on the rock surfaces. Though algae on rock surfaces is not usually harmful to aquatic life, it can make the water in your tank cloudy and dirty. Cleaning algae off fish tank rocks only requires a few steps and will help keep your fish tank clean and clear.

Things You'll Need

  • Hot tap water
  • Cool tap water
  • Salt
  • Bucket or container
  • Scrub brush or sponge
  • Paper towel
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Instructions

    • 1

      Wash and rinse your hands thoroughly. This will help you to avoid contaminating the water in your fish tank with germs or chemicals as you remove the rocks for cleaning.

    • 2

      Remove the rocks from the tank carefully.

    • 3

      Rinse the rocks under a stream of hot tap water to remove any excess dirt and debris.

    • 4

      Set the rocks aside on paper towels and fill a bucket or other type of container with cool tap water.

    • 5

      Add 1/4 cup of table salt to each gallon of water you use. Place the fish tank rocks in the water and salt mixture. Let them soak for at least 30 minutes.

    • 6

      Scrub the algae from the rocks with a scrub brush or sponge after you have allowed them to soak. The algae should be easy to remove. If it is not, let the rocks soak for an additional 15 to 30 minutes and scrub them again.

    • 7

      Remove the rocks from the water and rinse them thoroughly under a steady stream of cool tap water. Remove any excess salt from the rock surfaces.

    • 8

      Place the clean fish tank rocks on clean paper towels and allow them to dry.

    • 9

      Put the clean, dry rocks back into your fish tank. Monitor the water and rocks regularly to check for the return of algae growth. Repeat the process when the rocks appear dirty or the water becomes cloudy.