Most Effective Aquarium Filters

Aquarium fish and invertebrates, such as living coral, pollute the water in which they live. Aquatic creatures pass metabolic waste into the aquarium, which lowers the water quality. A number of different filters can remove toxins from aquarium water. Biological filters contain material on which beneficial bacteria grow. These bacterial cultures remove ammonia, nitrites and nitrates from the aquarium water. Ultraviolet filters destroy disease organisms and rid aquariums of unicellular algae. Chemical filters remove toxic waste material.

  1. Protein Skimmers

    • Protein skimmers or foam fractionators remove molecules of urine and feces before they break down and pollute the aquarium water. These highly effective filters are typically associated with marine aquarium keeping, but are also used by pond keepers, particularly those who keep koi. Protein skimmers are the only filters which completely remove waste material from the water as they operate.

    Ultraviolet Sterilizers

    • These tube shaped cylinders incorporate an ultraviolet bulb, which is sealed within a quartz glass tube. Ultraviolet sterilizers destroy unicellular algae that pass over the bulb, as aquarium water is pumped through the unit. Free-swimming disease-producing organisms that are exposed to the bulb are also destroyed. Aquarium water should ideally be pumped through mechanical and chemical filter material before being passed through the ultraviolet sterilizer. Ultraviolet light is damaging to the eyes and you must not look at a naked bulb that is operating.

    Biological Filters

    • These filters contain porous stones or similar material, on which beneficial bacteria grow. Aerobic or oxygen-loving bacteria grow on the outer surface of this material, where they convert toxic waste matter into nitrates. Anaerobic bacteria, which grow in an oxygen-depleted environment, colonize the tiny holes within the porous material and remove the nitrates from aquarium water. Biological filters can run moderately stocked aquariums, without the need to include any other type of filter. Aquarium biological filters are available in canister, trickle tower, hang-on and internal box filter types.

    Chemical Filters

    • These filters or filter compartments hold various types of materials, which remove toxic products from the aquarium water. Activated carbon is commonly the material in the chemical filter compartment. This highly porous material physically traps molecules of waste matter. You should replace activated carbon on a monthly basis, or the toxic products which it contains will leach back into the aquarium water. Chemical filters are normally included as compartments in canister and hang-on filters.

    Diatom Filter

    • These filters polish aquarium water by removing extremely small particles of detritus and debris. Diatomaceous earth, which consists of the skeletons of diatoms, physically traps particles as small as 1 micron. These filters remove disease-producing organisms, thereby creating a healthy living environment for aquarium fish. It is not necessary to operate diatom filters on a continual basis. You can run diatom filters during a disease outbreak and when aquarium water is cloudy.