What Kind of Filter Should I Use for a 55-Gallon Saltwater Aquarium?

Saltwater aquariums can make colorful and exotic additions to any home or office. However, they are much more difficult to care for than freshwater aquariums, which are much more common. Saltwater aquariums require much more delicate and powerful filtration than freshwater setups, and because of the large amount of water in a 55-gallon tank, an external canister filter comes highly recommended.

  1. Canister Filter

    • A canister filter is an external filter that uses two hoses to to bring in water dirty water and expel clean water. These filters, which typically sit below the aquarium, bring in water from the tank with an input line and run it through a filter medium. The filter then expels the clean water via the output line and back into the tank. Canister filters are generally quieter than other filters and use conical filter cartridges. The specific filter must be powerful enough to filter a 55-gallon aquarium. Look for the power ratings on the filter's packaging.

    Protein Skimmers

    • Protein skimmers are pseudo-filters that collect organic waste, usually using a foaming action, before they can turn into harmful chemicals. Protein skimmers collect waste in a collection cup that usually hangs on the outside of the aquarium; you must clean out this cup once a week. Only aquariums that incorporate coral require protein skimmers; they not necessary in setups that include only fish or live rock.

    Live Rock and Live Sand

    • Live rock and live sand are decor options that actually contain tiny organisms such as copepods, worms and featherdusters. These animals eat organic debris floating around in the water while providing food for your tank's larger inhabitants. You must cure live rock before before you can add it to a tank. Curing is the process of allowing certain organisms in the rock or sand to die with the rock in a separate container so the bodies do not add dangerous ammonia to the main tank. You must then properly acclimate it to the aquarium by adding small amounts of your tank water (usually by the drop) to the rock's existing water until it has fully adapted to the tank water.

    Hang-On Filters

    • Hang-on filters are basic filters that suck water up through a tube, push it through a filter medium usually consisting of a biomesh to catch debris and activate carbon to remove harmful materials, then expel clean water down a ramp known as a spillway. Hang-on filters often do not provide the powerful filtration needed for larger saltwater aquariums such as 55-gallon models. If you do insist on using a hang-on filter, it must have enough power to filter at least 55 to 75 gallons of water, and the tank should have minimal inhabitants to prevent excessive waste.