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Which Filter do I Choose?: |
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There are so many types out there, which
one is right for you?
So, you've gone to the pet store recently and you're thinking, "I'll
just pick up a filter," but when you get there, you see so many
types! There are canister filters, power filters, undergravel
filters, and that's just naming a few! Not to worry, this page will
break down the major types of filters, commonly available, for you
and even list some pros and cons.
Power Filters (aka HOT/HOB)
HOT and HOB stand for Hang-on-Tank and Hang-on-Back, and this is
exactly what the filter does. It hangs on your tank and as a tube
that is in the water. The tube sucks the water up and spits it back
out, into your tank, all clean and filtered. These are the most
popular type of filtration for goldfish, mostly because they are
cheap, plentiful, easy to acquire, offer many options, and do a
good job. Certain filters, like AquaClear filters, have sponges
to also add biological filtration, as well. (More
info on biological filtration)
Pros: Many price ranges, many choices, easy to find,
some models have very good biological and mechanical filtration,
easy to set up.
Cons: Not as good a filtration for larger tanks.
Undergravel (UG) Filter
As the name suggests, the majority of this filter is actually underneath
the gravel of your tank. The UG filter comes in two essential parts:
a "bed" and one or two tubes. The bed is what is placed underneath
your gravel, the tubes suck water from the tank, under the gravel,
through the bed, into the tubes, and out at the top. This filtration
is actually not recommended for goldfish because goldfish like to
forage in the gravel. The inverted water flow many times confuses
and annoys them, making it harder for them to forage for food. Another
thing that makes UG filters less desirable is the fact that you
need more gravel for the filter to function and more than 1" of
gravel usually causes more problems than its worth due to buildups
in rotting food and debris. Also, to clean a UG filter, you
must take out the bed. This requires totally breaking down the tank,
which kills much of the biological filtration and stresses fish
and plants.
Pros: very inexpensive
Cons: clogs easily, very difficult to clean/maintain,
not suitable for planted tanks, may go "bad" and create pockets
of rotting food/debris.
Power Heads
Power heads are not filters by themselves, but are used to "enhance"
filters. They are most commonly attached to UG filters to create
more filtration and water flow. But, many other filters also have
slots where a powerhead can be attached to increase circulation
and water flow.
Pros: increases water flow
Cons: not a filter by itself
Corner Filter
Corner filters are submersible filters that fit into the corner
of your tank. It's a small, plastic, hollow box that can be filled
with filter media, but usually its so small and weak, that it's
filtration is dismal. Nowadays, it's only used for fry or emergency
tanks, and even then, sponge filters are suggested.
Pros: very inexpensive
Cons: very weak filtration, small (not good for larger
tanks), frequent changes of filter media
Sponge Filters
Sponges are very simple, submersible filters consisting of a sponge,
tubing, and an air pump (or powerhead) to draw water through the
sponge, up the tubing, and back into the tank. The idea of a sponge
filter is a large amount of biological filtration with no mechanical
filtration. As a result, these filters are best for fry tanks (since
it's difficult for fry to get sucked up the tubes, and the water
flow is gentle) or quarantine/emergency tanks (since most medications
recommend that you don't use any mechanical filtration while medicating).
Sponge filters are also easy to clean: just pull off the sponge
and gently rinse the sponge in a bucket of old tank water.
Pros: inexpensive, easy to maintain, good for quarantine/emergency
and fry tanks, high biological filtration
Cons: no mechanical filtration, inadequate for larger
tanks
Trickle Filter (AKA Wet/Dry Filter)
A trickle filter sits underneath the aquarium, and is fed a steady
stream of water to a bacteria bed via gravity. The result is an
extremely large amount of biological filtration. Some filters have
a "prebed" which consists of mechanical filtration. The key to a
trickle filter is to keep the biological media (bio-balls, etc.)
suspended above the water. By the water merely trickling through
it, the oxygen-water combination stimulates a large amount of biological
filtration that can support a large amount of fish. These filters
are especially good for larger tanks.
Pros: supports large tanks and large amount of fish
Cons: expensive
Canister Filter
Canister filters sit underneath the tank, as well, and while they
are rather pricey, they offer a large amount of mechanical and biological
filtration. Many canister filters also allow you to customize the
type of filter media you place in the canister. They are efficient
and quiet. Water is drawn out of the tank via an intake tube, through
piping/hosing, and into the canister; then the filtered water is
then sent out through more piping/hosing and expelled back into
the tank via a spray bar. The result is a very powerful filtration
system. The only drawback is that canister filters can be a chore
to maintain and reassemble, and during power outages, unfiltered
water can leak back into the tank.
Pros: supports large tanks, high amount of mechanical/biological
filtration, choice of filter medias
Cons: expensive, chore to maintain/restart
Fluidized Bed Filter
Fluidized Bed Filters consist of a cylindrical pipe filled with
sand. Water is pumped through the filter and the sand, resulting
in massive bacteria growth. They are an amazing source of biological
filtration contained in a very small unit. Due to the high biological
filtration, they can support very large aquariums. Unfortunately,
these type of filters need a pre-filter (canister filter or power
filter) to act as a mechanical filtration, and the prefilter will
need to be cleaned weekly to maintain a high flow rate.
Pros: supports very large tanks, high amount of biological
filtration
Cons: expensive, needs a prefilter
Bio-Wheels
Biowheels consist of pleated filter material on a cylindrical wheel
which resemble the paddle wheels of a paddle boat. The wheel is
powered from water expelled from either power filters, spray bars
from canister filters, or powerheads. As the wheel spins, it exposes
the bacteria colony to the air allowing for higher levels of oxygen
exchange and thus a larger bacteria colony is able to grow. When
the bio-wheel does not turn easily, the bio-wheel can be dislodged
and rinsed in a bucket of old tank water.
Pros: supports a large amount of biological filtration,
maintenance free, inexpensive
Cons: not a stand-alone filter
Remember:
whatever filter you buy, it is recommended that it turns the water
of your tank 8x per hour. Goldfish are messy fish and they require
a lot of filtration. For example, if you own a 20 gallon
tank, you know that all 20 gallons must be filtered by the filter
every hour, 8 times. This is what the GPH (gallons per hour) is
for: it tells you how many gallons are filtered every hour. Now,
using a little math:
20 gallons x 8 times for filtration = 160
So, your
filter's GPH should be at least 160. Do not listen to what they
say on the filter box, it isn't enough for goldfish!
Next: Equipment
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