How to Clean Out 2-Year-Old Algae From a Dry Fish Tank

When fish tanks go into storage, they might have stuck-on algae from before storage. After two years of storage, the stuck-on algae is already dead and becomes crusted and dried on. When you get crusty, dried-on algae, cleaning it off and removing all of it is a necessity before you can put fish into the fish tank. Fortunately, cleaning it off is a relatively simple procedure.

Things You'll Need

  • Hose
  • Water
  • Cleaning gloves
  • Hard sponge
  • Scrub brush
  • Old credit card (optional)
  • Bleach
  • Chlorine-removing water conditioner
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Instructions

    • 1

      Take the tank outside. While you can clean a fish tank inside, it is easier to clean outside where you can dump the water directly into the ground.

    • 2

      Fill the tank with water, completely covering the stuck-on algae. Leave the tank to sit for one to two hours. This will help loosen the algae and make it easier to clean. Dump out most of the water, leaving only about 20 to 25 percent of the water in the tank.

    • 3

      Put on some cleaning rubber gloves or similar gloves and grab the hard sponge. Rub the sponge around the fish tank, scrubbing it hard to break up the algae. Scrub all of the sides and corners of the tank.

    • 4

      Dump out the remaining water. Spray the tank with a hose to rinse and dump out the water again. Fill the tank to about 20 percent with water.

    • 5

      Dip the scrub brush into the water and scrub the tank with the scrub brush. As before, scrub all of the sides and the corners. The scrub brush can get to those hard to reach areas in the corners better than the sponge. Dump out the water, rinse the tank and dump the water again.

    • 6

      Get out the old credit card, preferably one that has expired or is a closed account and not an active card, and scrape away any algae that continues to stay stuck on. This is only required if the scrub brush and sponge are not enough to remove the algae completely. You can also use a razor if you prefer, but a credit card will work. Avoid using a credit card or razor on an acrylic tank and instead continue scrubbing.

    • 7

      Rinse the tank one more time and then fill it until it's nearly full. Pull out regular chlorine bleach and pour it into the tank until the tank starts to smell like a strongly chlorinated pool. The exact amount will differ for each tank size.

    • 8

      Allow the tank to sit for 24 hours. The bleach will disinfect the tank and kill any bacteria or harmful elements to your fish.

    • 9

      Dump out the tank, scrub one more time with the scrub brush and rinse the tank out. Continuously rinse the tank for at least 15 minutes or more to remove the bleach and then allow the tank to air dry.

    • 10

      Fill the tank with water and treat it with chlorine-removing water conditioner according to the conditioner's instructions. This will remove the remaining chlorine bleach from the tank. After treating the tank for chlorine, it is ready to use for your fish.