Does a pond really need a
filter?
Absolutely! One of the most common problems that ponds
have is that they are under filtered. Putting in a
successful pond is more than just digging a hole, throwing
in some liner, tossing in a few rocks, and adding a
waterfall. It requires good water flow, a filter for
waste management, and
a skimmer to pull debris off of
the surface before it can contribute to waste in the pond.
If you try to cut corners and not put
in a filter, you are in for a world of hurt after a couple
of weeks. Your pond will begin to collect debris
(leaves, sticks, fish poop) at the bottom, and as it starts
to decay ammonia will be released. Ammonia is toxic to
life and it can kill everything in the pond in a day or two.
So, what kind of filter do I
need?
If there were a quick answer to
this, we would probably be sipping Mai Tai's in Tahiti
instead of writing this FAQ. It's not that it is a
difficult question to answer - it's just that there are a
lot of possibilities.
Let's start with a quick review of
the types of filtration and what they do.
|
Type of
Filtration |
Purpose |
Example |
| Mechanical |
Removes debris |
Skimmer, filter mat |
| Biological |
Good bacteria
"condominiums" |
Pond Matrix (porous stone) |
| Chemical |
Removes
organic waste |
Carbon, phosphate remover |
Mechanical Filtration
Mechanical filtration removes
debris such as leaves, sticks, excess food, and larger
particles of crud from the pond. Physical waste
removal is important because the less waste that is put into
the pond, the less food that there is to feed algae.
One of the most important types of
mechanical filtration is a skimmer. Pond skimmers work
under the same premise as pool skimmers. A pump
creates suction that causes water to pull into the skimmer
along the side of the pond. This flow will pull
in debris that is floating in the water. Typically
there is some sort of leaf basket or leaf net that catches
the largest debris like leaves. That is usually
followed by a piece of filter mat that catches smaller
particles. This mat keeps debris from entering the
pump and it can be rinsed off periodically to remove waste
from the pond.
Choosing a Skimmer
If you are installing a liner, plan
for one that attaches to the side of the pond like the one
on the right-hand side below. You cut a hole in the
side of the liner and then secure the skimmer via silicone
and the removable ring that bolts onto the skimmer box
to hold the liner in place.
 |
|
 |
|
Tetra In Pond Skimmer |
Atlantic
Water Gardens Pond Skimmer |
Skimmer
Parts |
If you have a pre-formed pond or
you have inherited a pond that does not make installing a
standard skimmer possible, opt for an in-pond style skimmer,
such as the Tetra skimmer pictured above on the left.
They can sit anywhere in the pond and can be supported by
rocks or concrete blocks to place it at the correct height.
Speaking of which, always remember to use a level when
installing a skimmer and keep in mind that the height of the
skimmer determines how high your water level will be in the
pond. In our pond maintenance experience we have run
across several ponds where the skimmer flap has been
removed. Always leave that in-tact because the skimmer
will not be able to skim the water's surface properly
without it.
Biological Filtration
Biological filtration is critical
to overall pond health. Biological filtration is
performed by billions of tiny bacteria that live on surfaces
in the pond. When setting up a pond it is important to
create as much biological filtration as possible. Many
people add "biological media" or "bacteria condominiums" to
the top of their waterfall filter which is also called a
"weir" (pronounced like "we're"). Biological media can
consist of Seachem's pond matrix (a type of super porous
rock), lava rock, bio-balls, or pea gravel when it
completely covers the bottom or is used in a bog.
 |
 |
| Tetra
Waterfall Filter |
Waterfall filter powered by a pump |
To get your biological media full
of bacteria, you add bottled bacteria such as
Seachem's Stability or Microbe-Lift to the water. Be
sure to turn off UV filters for 48 hours after adding
bacteria so that they have time to land on and colonize the
bacterial media. If they are still floating around in
the water when your UV filter is running, they will get
nuked.
Most waterfall filters have a
filter mat in them. Remember that your filter mat
houses a lot of bacteria, even though its purpose is
primarily mechanical filtration. If you need to spray
out your filter mat with a hose to get it clean, you should
add more of your bacterial additive to the water to
help make up for those lost bacteria. Without a
healthy amount of bacteria, you can have too much ammonia
and that can kill all of your fish.
Chemical Filtration
Chemical filtration works on a
microscopic level. Two of the most common types of
chemical filtration for ponds are carbon and phosphate
remover. Both of these filtration types grab large
organic molecules that would otherwise feed algae and keep
them bound up until you remove and dispose of them.
When you set up your pond be
certain that it includes each of these elements so that your
pond experience is successful. |
