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Freshwater
The Undergravel
Filter Controversy
The
undergravel filter (UGF) controversy has been
raging for years. As modernization of aquarium
filtration products advances, many aquarists think the need for a UGF
has long past. However, some still feel you can’t run your aquarium
without one. To help you make the decision of whether to use a UGF as a
basic component or not, start by understanding what the purpose of the
UGF is.
The two basic things you
want in your aquarium is a good filter media base for strong biological
filter growth, and clean, clear water. The UGF is a plate type filter
that is designed to pull water down through a media base (substrate)
that sits on top of the plate, trapping particles in the media as the
water passes through it. The surface area of the substrate acts as your
biological filter base. A UGF is run by an air pump and air stones, or
some types can be used with a powerhead. These filters can be very
effective, but are best used in tanks under 55 gallons in size, and are
NOT appropriate for use in reef tanks. The trick is to keep the
media clean, via a regular maintenance schedule. If a UGF is not
maintained properly the media builds up an accumulation of detritus and
other organic matter, which in turn contributes to a build up of high
nitrate levels. Another factor is that underneath the filter plate, dead
spots can form. This opens the door for the growth of unwanted bad types
of bacteria that may contribute to poor water quality in the long run.
The key to success when using a UGF is maintenance. With proper UGF care
these negative factors are greatly reduced and should not present a
problem.
Here are some pointers to
help insure that your UGF runs properly:
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The media base needs
to be thick enough to trap the particles, but not so thick that it
defeats the filtering process. A layer of about two inches of fairly
coarse material should be sufficient. If the media is too fine it
will clog the filter plate, and if too course it won’t trap the
particulates as it should.
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Make sure you have
sufficient air/water flow in all areas under your UGF. Dead spots
will allow bad bacteria to grow, as bad bacteria grows in oxygen
depleted environments.
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Be sure to use an air
pump that has sufficient volume to draw the water through the media
and UGF plate.
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Use a hang-on-tank
type canister filter as a pre-filter to help remove particulates
that are free floating in the aquarium water. This can help to
remove and cut down on the organic matter that is drawn down into
the media. We recommend a Magnum 350 by Marineland
for this purpose. No matter what type of pre-filter unit you use, be
sure to clean or change the pleat cartridge, floss or sponge several
times a week, or as soon as it starts turning brown. You can tell
when it needs changing, the water flow rate begins to decrease
noticeably.
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Another feature of the
Magnum 350 or H.O.T. model is that it has a siphon tube attachment
that you can hook directly to the filter intake and clean your media
with ease. When you siphon the media it only pulls out the junk,
leaving the media behind, then sends the water through the canister
where the pleat cartridge captures the organic matter, and then
dispenses the clean, filtered water back into the tank. This makes
for a simple and quick way to clean the media on top of the UGF
plate. It even works great for quick surface cleaning on most any
type of substrate in other types of system set ups as well.
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Some UGF’s are
designed as reverse flow set ups. This type of UGF allows for back
flushing of the area underneath the filter plate, which in turn can
aid in simpler and more effective cleaning of the filter.
Get to know your tank and
work out a regular maintenance routine. Do your research on the various
types of undergravel filters on the market, and how each works.•••
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