How to Clean a 90 Gallon Fish Tank

Nature provides rocks, water flow and bottom feeding aquatic life to keep waters clean and pure. Cleaning a 90 gallon fish tank requires removing extra debris while maintaining a balanced eco-system within the tank. Cleaning your tank monthly prevents the buildup of toxic gases and chemicals that can kill fish. It should take approximately two hours to completely drain and clean a 90 gallon fish tank.

Things You'll Need

  • Aquarium fish net
  • Long siphon tube
  • 10 gallon plastic bucket
  • All-purpose clamp
  • Fish algae scrub brush or roll of paper towels
  • Thermometer
  • Aquarium water neutralizer
  • Disposable or tin pie pan
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Instructions

    • 1

      Turn off and unplug all lights, filtration systems and thermometers. Remove the tank hood and lid assembly. Set aside. Remove all plants and decorations from the fish tank. Set aside. Leave fish inside the tank.

    • 2

      Rake your fingers through the bottom gravel to bring debris from beneath the rocks to the surface.

    • 3

      Place an aquarium fish net tightly over the end of a siphon tube to prevent siphoning out any of the fish. Place this end of a siphon tube into the fish tank. Suck on the other end until the siphon tube is half full. Direct siphon tube to a 10 gallon collection bucket. Siphon water.

    • 4

      Fill bucket three-quarters of the way full with dirty fish tank water. Fold end of siphon tube over. Clamp siphon tube to prevent further siphoning.

    • 5

      Empty bucket in garden, yard or toilet. Repeat steps 3 through 5 for 40 gallons of water removal from tank. Clamp off siphon tube and allow to rest in tank and bucket.

    • 6

      Wash and scrub plants and decorations with hot water.

    • 7

      Smooth gravel with the palm of your hands. Replace plants and decorations. Wait two hours to allow tank water and any remaining debris to settle.

    • 8

      Unclamp siphon tube and slowly siphon in a back and forth motion to remove large areas of debris settlement on top of the gravel. Follow steps 3 to 5. Remove no more than 20 more gallons of water.

    • 9

      Scrub the sides of the tank with a fish algae scrub brush or dry paper towels. Only clean two-thirds of the surface glass area. Dispose of towels or set aside scrub brush when glass is clean.

    • 10

      Stop siphoning and remove tubing from tank.

    • 11

      Rinse bucket with hot tap water to clean out any old fish tank water or debris.

    • 12

      Take the current temperature of the tank water. Run tap water from your sink until temperature matches within 10 degrees Celsius of the tank water temperature.

    • 13

      Place aquarium water neutralizer into the bottom of the bucket. Different types and strengths of aquarium water neutralizer are available. Follow the ratios provided on the container's instructions.

    • 14

      Fill the bucket three-quarters of the way full with the water. Make certain it is the right temperature (see step 12).

    • 15

      Place a disposable or tin pie pan in the center of the tank on top of the gravel. Slowly pour the water into the tank, directing it on top of the pan.

    • 16

      Replace items removed in step 1. Plug in and turn back on all items disconnected in step 1.