How to Control Red Hard Algae in a Salt Water Aquarium

There are approximately 6,000 different types of red algae, or Rhodophyta. Red hard algae features a calcified outer shell that helps it resist wear and damage. Many aquarium owners consider the algae beneficial to the tank̵7;s environment, while others see it as a nuisance that steals precious nutrients from surrounding plant life. Killing red algae inside your tank involves modifying the water̵7;s conditions to create an unsavory environment for the algae to thrive.

Things You'll Need

  • Coral
  • Tap water
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Instructions

    • 1

      House the aquarium away from any windows, especially those that receive direct sunlight for more than eight hours a day. Restricting the amount of sunlight the tank receives cuts down on red algae growth.

    • 2

      Provide the aquarium with no more than eight to 10 hours of artificial light per day. Turn off the aquarium̵7;s light to prevent the algae from receiving the nutrients it requires to thrive, and multiply.

    • 3

      Introduce coral to the saltwater aquarium. The coral provides competition for nutrients, making it difficult for the algae to thrive.

    • 4

      Feed the fish once a day. The excess food creates a greater amount of nutrients in the water.

    • 5

      Lower the amounts of phosphates in the water. Feed the fish flakes with low-phosphate levels, clean the filter regularly and fill the tank with deionized water, which is naturally lower in phosphate than tap water.

    • 6

      Remove any dead fish from the tank immediately. The rotting fish releases nutrients, including phosphates, the algae need to survive.