Thursday, April 26, 2007

Koi Pond: Biological Filters

Contrary to common belief, biological filters do not
process or filter the solid waste of fish in your koi pond.
 They continue to build up and putrefy, creating a breeding
ground for harmful species of heterotrophic bacteria which
are pathogenic to koi fish. As stated, the biological
filtration process utilizes Nitrosomonas bacteria to break
down ammonia into nitrite and nitrobacter, further
converting nitrites into nitrates, which is less harmful to
koi fish.

Plants now utilize the nitrate and phosphate for
fertilizer; if you have not provided an adequate ratio of
water plants to koi fish, "hard" algae (growing on rocks
and koi pond walls) and "free- floating" algae use nitrate
and phosphate to reproduce.

The key to preventing this condition, called "algae bloom,"
is to provide enough non-soil bearing plants such as water
lettuce and hyacinths to compete for the nitrate and
phosphate.  Since these two plants are tropical and can
only survive in warm climates, hardier varieties such as
Elodea and Anacharis will perform well in cold climates.
These plants are commonly used in bio-filter ponds.

A bio-filter pond is used in conjunction with shallow koi
ponds with small populations of koi fish.  It will also
eliminate the need for a mechanical bio-filter and  a
second pump to operate it.

The bio-filter pond is located higher than the main pond
for two reasons. It prevents the koi fish from eating the
plants and it allows the water from the waterfall to be
filtered as it passes through the plants prior to spilling
into the lower koi pond.

An adequate ratio of plant cover for the koi pond's surface
is approximately 20 to 30 percent.  This is a basic rule of
thumb and many factors can change this equation.

For example: koi fish population, water temperature, and
debris accumulating from leaves or over-feeding the koi
fish. I have said many times that the Koi Pond is the koi's
living room, dining room and toilet.

If you do not have a bio-filter, that could explain why
your koi pond is a tad green, stinky, or cloudy, and why
your finned family is gulping air on the surface. Trust me.
 That will not be for long. Fish gulping air to survive
would be like you -- in an attempt to avoid breathing
poisoned air -- gulping water to survive.

If you do not already have a biological filter, I can not
encougage you enough to abtain one. If your pond is over
eight hundred gallons, and you are using an above ground
pump that produces over 3500 gallons per hour, I suggest a
pressurized bead filter. I cover the topic of biofilters in
greater detail in another article.        Happy koi, peace
and joy.


----------------------------------------------------
Douglas C. Hoover; CEO of Aquamedia Corp, master Waterfall
Builder, freelance writer and author designer, architect,
inventor, engineer, writer, author and builder of over
1,900 waterfall and ponds in California or the past 26
years. Read my other articles at:
http://www.ezinearticles.com  Have a question?
http://www.askdoughoover.com