How to Clean a Marine Aquarium

Written by kasandra rose
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How to Clean a Marine Aquarium
Monitor and clean your marine aquarium weekly. (hide and seek image by cherie from

Marine aquariums are more difficult to clean than freshwater tanks. The salt tends to "creep" onto the powerheads and the glass lid and even down the outside of the tank. To remain attractive, it's important that these surfaces be cleaned frequently. Clean the salt deposits no less than once a week and as often as once a day. You must consider the material that the tank is made from when selecting your tools.

Skill level:

Things you need

  • Acrylic or glass scrubber pad
  • Long handled scrubber pad
  • Siphon tube
  • Bucket
  • Thermometer
  • Aquarium salt
  • Hygrometer
  • Scraping blades

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  1. 1

    Obtain the type of pad scrubber and scraping blade meant for your type of aquarium. Acrylic aquariums are much easier to scratch than glass and need no-scratch pads.

  2. 2

    Prepare replacement saltwater a day in advance if you intend to clean the gravel. Gravel cleaning should be done monthly. Mix aquarium-approved sea salt with water as directed by the sea salt manufacturer.

  3. 3

    Test the specific gravity of the new saltwater and your aquarium using the hygrometer; aim for a specific gravity of 1.26. Dip the hygrometer into the fresh sea salt mixture and fill it to the line. Read the specific gravity of the arrow. If your aquarium salinity has increased due to evaporation lower the specific gravity of your replacement water slightly to balance the loss.

  4. 4

    Turn off the pumps and any heaters that will become exposed to the air to prevent splash damage or overheating.

  1. 1

    Place a large, empty bucket near the aquarium if using a gravity-feed siphon. The bucket should be large enough to hold more than the total water you intend to change and sturdy enough not to rupture with that volume of water.

  2. 2

    Prime the gravity siphon with its priming mechanism. Place the large end of the siphon tube in the water, pump the water through the tube and then allow it to flow into the empty bucket.

  3. 3

    Start the siphon by mouth if no priming mechanism is present. Place one end of the siphon in the tank and suck on the other end of the tube. Watch where the water is in the line. When the water in the tube reaches below the water level in the tank, slip the open end of the tube into your empty bucket.

  1. 1

    Attach the siphon to the sink faucet by screwing the adaptor onto the threads on your faucet. You may need to remove your faucet aerator first.

  2. 2

    Close the valve near the open, siphon-tube mouth, preventing accidental water spillage.

  3. 3

    Set the siphon to remove water from the tank by opening the release on the faucet adaptor. Water should be pouring into the sink through the siphon faucet adaptor when you turn the faucet on and no water should be coming from the siphon tube.

  4. 4

    Open the valve at the end of the siphon mouth. Hold it over the sink and listen for the sound of air being sucked into the siphon. If water comes out instead of air the adaptor is not set for water removal. Correct the setting.

  1. 1

    Plunge the siphon mouth into the aquarium. Hold the mouth of the siphon an inch or so above the substrate and suck up any eaten food or waste on the surface. Avoid sucking the substrate into the siphon; you don't want to disturb your healthy bacteria. Stop removing water at 20 per cent or when your bucket is full.

  2. 2

    Clean the inside glass with the scrub pad, using the long handled brush to get to hard to reach areas. Do the front of the glass and possibly the sides but leave the back glass alone.

  3. 3

    Scrape stubborn algae off the inside front of the tank with a scraper.

  4. 4

    Test the temperature of the replacement water using the thermometer. Use a heater if necessary to get it near the same temperature as your tank water. Fill the tank with the fresh saltwater.

  5. 5

    Remove the light hood, and clean the top and bottom of the glass lid in the sink. Dry and replace the lid on the aquarium.

  6. 6

    Wipe all exterior surfaces with a soft, wet cloth to remove salt deposits. This can be done daily. Rinse the cloth frequently and finish by wiping the glass with a dry paper towel.

  7. 7

    Plug in all your pumps and heater. Observe them to ensure they are working correctly. Dispose of the dirty salt water.

Tips and warnings

  • Clean all your equipment immediately before the salt dries on it.
  • Gravity siphons, while inexpensive, can lead to messy mistakes if the bucket overflows.
  • Don't disturb your live coral or sand.
  • Prevent fish from being sucked into the water siphon. Some siphons come with guards over the ends to prevent accidental fish capture.

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