Page 309 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

PUMPS AND FILTERS 307

POND FILTRATION EQUIPMENT
The pump is a critical component of a filtration system, providing the Pond filtration systems work on the same principles as aquarium filters
power to force the water through the filter unit. All designs of pumps, (see pp.34–35), albeit on a much larger scale. Water from the pond is
from submersible units to more powerful surface models, work on a passed through an internal or external filter unit that contains layers
similar principle: an electric motor draws water through the unit and of filtration media. These can include brushes or layers of filter foam
expels it through an outlet. Most pumps are equipped of different grades that sieve particulate matter from the water
with a pre-filter—ranging from sieve-type fixtures Outlet to fountain and also serve as biological filtration media, on which beneficial
to foam-sponge attachments—which helps bacteria can grow. The bacteria break down ammonia produced
to prevent debris in the pond from entering T-piece allows pump to be by the fish, as well as other waste matter. Having passed
the pump unit and causing a blockage. attached to filtration system through the media, the clean water then returns
to the pond via the outflow or can be run
Flow rate adjuster, held in
Submersible pumps are place with a hose clip through a further series of filters
designed to operate underwater to maximize the water quality.
and will not function outside the Check the filter flow rate and water
pond. An electric motor within quality regularly; any drop suggests
the pump unit drives an impeller, that the filter needs cleaning. When
which forces water out of the Water is drawn cleaning a pond filter, always wash the
in through
pump through the outlet. This slits in the outer media in dechlorinated or pond water,
creates a flow through the unit casing to safeguard the bacterial population.
that draws water into the pump. In a new pond, it will take time for
The outlet can be connected to beneficial bacteria to develop in the
a pipe that leads to a filtration Electric motor with filter. To make sure ammonia does not
system or can supply a fountain attached impeller build up to dangerous levels, add
or a waterfall. zeolite—a compound that removes
Impeller helps to drive ammonia from water—to the filter.
Strainer traps material that water through the unit
could clog the impeller Water pumped
Overflow pipe, which carries water Spray out of the pond
back to the pond if the filter is blocked enters the filter
through the
inlet pipe
The main chamber of an external filter unit is housed outside the pond.
Water is pumped in at the top, where it is delivered, as a fine spray, onto the
filtration media. It first passes down through a number of foam layers—
from coarse to fine—where particulate matter is trapped, and then through
a layer of biological media, before being returned to the pond.
Layers of foam help
to sieve the water
Unit can be hidden behind
suitable vegetation but must
be accessible for maintenance Plastic tubing
through which
Filter unit water exits the Plastic biomedia in
filter the base of the filter
Return pipe concealed encourages growth
under rocks of beneficial bacteria
Clean water flows
back into the pond
A typical pond setup uses a
submersible pump to supply an
Water is pumped
out of the pond external filter by the waterside.
to the filter unit Pond water is drawn Pumps that are used for passing
into the pump water through a filtration
system should be robust enough
not to become choked by debris
from the pond. If sufficiently
Pump positioned powerful, a pump can be
on a solid base
employed to operate a waterfall
or fountain in addition to
supplying the filtration system.

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