Page 213 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

HEATING AND FILTRATION 211

FILTRATION CHOICES Air enters to aerate water
Two or more filters are often used in the same tank to Electrical power
cable
maximize water quality and eliminate ammonia and nitrite,
which reef fish cannot tolerate. Biological filters, such as
undergravel and trickle designs (right), are often teamed with Beneficial bacteria Powerhead pumps
external power filters, which pump water through an external colonize substrate water up from beneath
canister containing filter media such as sponge, filter wool, or the filter plate
activated carbon. The filtered water is then sprayed back into Water is drawn up
the tank through the fine holes of a spray bar—a process that the uplift tube
helps oxygenate the water. Some aquariums feature ozonizers—
units that produce bubbles of ozone gas to oxidize waste
matter—or protein skimmers (below), which use yet another Filter plate sits Water drawn
on tank floor
method to remove potentially harmful organic waste. through perforated
filter plate
Foam spills over In an undergravel filter, a colony of beneficial bacteria establishes itself in the
into reservoir substrate. As water is drawn down through the filter bed, the bacteria break
down organic waste produced by the fish. However, a power filter is a more
Air efficient option.
Waste collects
in reservoir Water passes Water is sprayed Tube carries water
through activated onto filter plate up from tank
carbon filter Tiny holes in
medium filter plate
allow water
Bubbles carry to trickle
protein waste through slowly
upward as they rise
through the water
Layers of
progressively
Air is pumped finer filter
into the skimmer Airstone produces media
tiny bubbles
Clean water
drips back Slit allows water to Biological filter medium
into tank pass to next section harbors beneficial bacteria
The protein skimmer works in a different way from conventional filters. A stream The trickle filter provides sophisticated biological and mechanical filtration.
of electrically charged air bubbles rises through a plastic tube; proteins and other Water is drawn up from the tank and sprayed over a stack of different filter
organic wastes stick to the bubbles and rise to the surface, where they form a media, through which it trickles before flowing back into the aquarium.
thick foam. This must be regularly collected for disposal, preferably twice a week. Spraying also oxygenates the water, improving bacterial action within the filter.

for bacteria that convert these natural
waste products into harmless compounds.
Mechanical filters remove particles by WATER STERILIZATION
forcing water through some kind of filter Ultraviolet (UV) light is a powerful sterilizing agent, capable of
cartridge. Some of these cartridges contain killing bacteria, parasites, and even tough algal spores. Some
filter media that trap particles as small as aquarists use sterilizing units that pass water from the filter
3 microns across and can be used over a UV lamp before returning it to the tank. There is some
periodically to scrub the water of evidence that use of these lamps reduces the incidence of disease.
bacteria and algal blooms. Chemical Water travels Water is pumped into the
filters remove dissolved substances from back into the tank unit from the power filter
the water, such as ozone, chlorine, heavy Water flows The UV tube in the
metals, and medications. Most work by around UV lamp sterilizer unit should
forcing the water through a filter medium be replaced every six
months, because
of activated carbon (a manufactured form of output drops quickly.
carbon that is highly porous). Chemical filters Looking directly at
this light source will
are useful for eliminating the yellow coloring UV lamp damage your eyes.
that often develops in aquarium water.

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