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Ponds Introduction
Pond Design
New Pond Setup
Filtration
Algae Control
Lighting Your Pond
Water Plants
Pond Fish
Return to Landscape 101
Algae blooms are a common occurrence in outdoor ponds. Most
outdoor ponds are closed re-circulating aquatic systems
which lack a fresh water flow through source. In these
closed systems, nutrients and carbon dioxide will build up
and create two classes of Algae; Planktonic algae and
filamentous algae.
Planktonic Algae
Planktonic algae are waterborne single cell algae. Planktonic
algae turn the water green. This is called an Algae bloom.
Sunlight and the nutrients and carbon dioxide in your pond’s
water combine to create algae blooms. The nutrients come
from uneaten fish food, fish waste including ammonia, and
organic matter such as decomposing leaves. The more
sunlight a pond receives, the better the chances of algae
forming in your water.
The most effective method of Planktonic algae control is
ultraviolet sterilization. Artistic Landscapes has used
ultraviolet lights from many different manufacturers. We
have concluded that the most effective ultraviolet lights
for both performance, longevity and ease of use are Smart
U.V.’s manufactured by Emperor Aquatics. These products can
be seen at
www.emperoraquatics.com. A more detailed description
of ultraviolet lights is given below.
Planktonic algae can be controlled with aquatic plants,
shade, ultraviolet sterilization or chemical methods. Using
aquatic plants as an algae control requires that a specific
number of mature plants are added to the pond to compete
with the algae for the available nutrients and carbon
dioxide. Our experience shows that if enough sunlight
reaches the pond, algae are likely even with plants. If the
plants create enough shade, algae can be prevented. Shade
is available only if foliage or a shelter inhibits the
pond’s exposure to sunlight. Some Koi enthusiasts have
constructed a shelter over their pond with a black netting
to protect the water from the sun. While effective, it is
not natural in appearance. Chemical treatments can be
successful, but they can be expensive, temporary, and
potentially harmful to plants and fish.
UV sterilization is a proven method for controlling
waterborne algae. Combining sterilization with adequate
mechanical filtration and operating the two properly is most
effective in eliminating algae blooms and maintaining clear
water. This combination will not, however, control nitrogen
or carbon dioxide levels. Practical fish stocking densities
and responsible feeding, along with routine filter and UV
sterilizer maintenance play a big part in achieving a
balanced system. Partial water changes (approximately ten
percent of the pond volume weekly with non-chlorinated
water) will aid in diluting nutrients.
Algae blooms can be controlled with an ecologically balanced
pond. Seeding your pond with bacteria such as Microbelift
is the quickest way to achieve this balance. Plants are
essential to maintaining an ecologically balanced pond.
Plants eat the same food as the algae (nutrients) while also
absorbing the suns rays. Light and nutrients are the food
of both plants and algae. Water lilies provide shade to the
water while providing beautiful flowers. Water hyacinth and
water lettuce also shade the water and their floating root
systems absorb nutrients needed for algae. These plants
reproduce rapidly. They are best suited for the biofalls
surface, and can be kept in place with fishing line. Throw
away older plants. The roots of these plants if placed in
the pond itself are a favorite food for fish, especially
Koi. In fact, Koi will eat all of these plants in the
pond. Your water lettuce will soon become shredded lettuce.
Biofiltration will eat the nutrients needed for algae as
well. Biofilter medium in the biofalls and gravel at the
bottom of the pond are great places for bacteria to
colonize. Another great place is a bog pond or veggie
filter. This is a shallow section of the pond that the
pond's water circulates through, usually at the top of a
waterfall. Fine meshed foam pads can also remove algae from
the water. Never use lawn fertilizer or plant insecticides
near your pond, as these will cause large nutrient blooms
that may threaten your aquatic life.
If your pond currently is full of algae, the quickest way to
clear the water is to install a U.V. light and perform a
partial water change. Once the water has cleared, bacteria
such as Microbelift should be added to the pond. The U.V.
light needs to be turned off for 48 hours after the bacteria
are added. The U.V. light will kill new bacteria. Once a
good bacteria colony has been established, enough new
bacteria will be produced to offset the bacteria killed by
the U.V. light.
The lamps in a U.V. light burn out every six months. If
used, they need to be placed AFTER the filter, because they
kill the nutrients needed by bacteria, which break down
waste materials in the pond. Keep your pond free of
debris. Clean your skimmer net on a consistent basis,
especially in the spring and fall. If your eco-balanced
pond turns murky, it may be time to clean the foam pads in
your filtration system.
Filamentous Algae
Attached filamentous algae can be seen growing on the rocks
of a waterfall or on the sides of the pond. The growth of
filamentous algae results from high levels of nutrients,
carbon dioxide, and the catalyst, the Sun’s energy. Methods
of controlling filamentous algae include increased shade,
reducing the frequency of fish feedings, practical water
changes, and the use of chemicals or plecostomus
(algae-eating fish) during the summer months. Ultraviolet
lights are ineffective in killing filamentous algae because
these algae, attached to objects in the pond, will not pass
through the U.V. light. Filamentous algae may grow and will
benefit the pond by consuming nutrients and carbon dioxide.
Responsible fish feeding will encourage the fish to graze on
the filamentous algae, which is good in their diet.
Filamentous algae may also be harvested and used as a
fertilizer in gardens; remove it by hand or with a
long-bristle brush.
Algae Isn’t Bad, Is It?
Algae can be either beneficial or detrimental to a pond,
depending on the owner’s viewpoint. Algae provide nutrients
for newly hatched fry, and indirectly act as a color
enhancer. As algae grow in a pond, a population of
zooplankton will also develop, on which the fish feed. These
natural live feeds help develop the intense coloration
desired in most Koi. Unfortunately, algae blooms prevent
viewing the fish, so that sick fish can go undetected for
days or even weeks.
Algae influence the water quality of the pond mainly by
affecting the balance among dissolved oxygen, pH, carbon
dioxide, and nutrients. During photosynthesis, algae produce
oxygen, remove nutrients, and take up respired carbon
dioxide from both the fish and the algae itself. In heavily
stocked ponds, the water becomes supersaturated with carbon
dioxide. High levels of carbon dioxide can quickly depress
the pH of the water to levels below seven if the operator is
not careful to maintain proper alkalinity levels and
adequate aeration for stripping. During active periods of
photosynthesis (during daylight hours), algae can quickly
strip the carbon dioxide out of the water, and pH levels can
rise above nine in a matter of hours. Fish not acclimated to
such sharp shifts may initially show signs of stress. At
night, both algae and fish consume oxygen from and exhale
carbon dioxide into the system. Algae compete with the fish
for available oxygen in the water.
Experience has taught us about other filtration methods as
well.
Bead filtration systems, or converted sand filters used for
swimming pools filter are not effective in handling the
larger volumes of organic matter and waste found in a living
aquatic system. Debris, living bacteria and algae can clog
these filters and render them ineffective. Swimming pools
use chemicals that would kill aquatic life to keep the water
clear and reduce the amount of debris required for the
filter to clean.
Pumps placed inside the pond become clogged with debris,
losing efficiency and destroying the pump. A pump, its
pipes, and an electrical cord inside the pond are unsightly.
At Artistic Landscapes, we believe that for a pond stocked
with fish, an Ultraviolet Light is an essential part of the
filtration system for both water clarity and waterborne
pathogens. UV sterilization is a proven solution to
waterborne pathogens commonly associated with aquatic
re-circulating systems. UV treatment only takes place inside
the UV exposure chamber and leaves no residual downstream,
and therefore is harmless to the animals in the pool. UV
sterilization is a proven solution to waterborne pathogens
commonly associated with aquatic re-circulating systems.
Filamentous algae and pathogens attached to objects and
lining of the pond will not pass through the ultraviolet
light and are unaffected by this filtering method.
UV sterilizers can kill waterborne pathogens. However
the water flow rate must be slower to increase the exposure
time between the microorganism and the UV light. The
clearer the water, the greater the UV light penetration.
Ponds Introduction
Pond Design
New Pond Setup
Filtration
Algae Control
Lighting Your Pond
Water Plants
Pond Fish
Return to Landscape 101 |
