These
pages are reprinted from www.gotalgae.com, courtesy of www.kascomarine.com.
The following sections covers types of common algae, its causes
and cures.

What
is Algae?

Algae
is often a catch-all for all aquatic plants and aquatic
plant related problems. this page separates the two for this
reason. Not all aquatic plants are algae. Also, not all algae is
created equal when it comes to how desirable or undesirable it is
in your pond.

Part
of the reason many call all aquatic plants algae is because even
experts differ on what to call or classify algae. Defining algae
is very difficult, but basically, algae is a simple organism that
can be composed of one cell or many cells grouped together in a
colony. There are three basic types of algae, planktonic, filamentous,
and attached or erect forms.

Planktonic
algae are single-celled, microscopic plants which are distributed
worldwide. Blooms can be bright green, pea soup looking or even
a blood red color. They are the base of the food chain and a healthy
existing pond or well prepped new pond must have planktonic algae
as a food source.

Filamentous
algae are called many things such as pond scum or moss,
and they are typically found at the surface in the form of greenish
mats. Typical growth begins on the edges of ponds and will slowly
rise until it arrives at the surface. This series of cells joined
together has a slimy, cottony or course texture. It can look like
the stringy masses covering the Algae Monster at the top of the
page or it can be "scum" as in the picture to the left.
Filamentous algae will grow in ponds with higher levels of calcium
and phosphorus. It is common to have this type of algae encouraged
after ponds are limed to enhance fish production. Filamentous algae
typically are of little or no value to you or your pond.

Attached-erect
algae are non-rooted but dense. A misconception is that
it looks like a higher vascular plant, which causes a lot of confusion.
It typically has a gritty and bristly texture and is not much use
to the overall pond health.

Blue-Green
algae is often the biggest culprit when it comes to "pond
scum" problems. Recently, it has been reclassified in the Monera
Kingdom which consists of bacteria instead of being classified with
other types of algae because the blue-green algae relates more closely
to bacteria than other forms of algae. Within the blue-green algae
grouping, there can be several varieties that can have many different
colors such as red, brown, or yellow. Blue-green algae are nitrogen-fixing
organisms and only need nitrogen and carbon dioxide to live, both
very prevalent in most ponds. When there is a blue-green algae bloom,
it forms dense masses on the surface of the pond and can cover the
entire body of water. In fact, it is believed that the Red Sea was
given its name from a red species bloom of blue-green algae.

Algae
in general serve a purpose and are essential for a healthy pond.
Planktonic algae is the first link in most food chains that occur
in your pond and your pond ecosystem needs algae. Zooplankton feed
on planktonic algae and bait fish and
fingerling sport fish in turn feed on the zooplankton. Without
a food source, the bait fish and fingerlings will struggle and not
thrive in your pond. Often times, pond owners who are managing their
pond for trophy bass production will fertilize their ponds to keep
the planktonic algae population very high. This serves to provide
more food for zooplankton, bait fish and fingerlings and also blocks
much of the sunlight from reaching the bottom of the pond. In turn,
other aquatic plants struggle which decreases the areas for bait
fish to hide and gives the bass a much easier meal to come by.

Often
the most frequent complaint about algae is aesthetics. A green pond
covered with algae is unsightly and is an eye sore. The enjoyment
of the pond or water feature is diminished when algae has taken
over.

Algae
poses a problem to your pond health when you have too much algae
and during algae blooms. During the photosynthesis process when
plants use sunlight and carbon dioxide to produce food, they give
off oxygen. Photosynthesis is a good process for your pond. The
plants are using carbon dioxide and giving off oxygen which is needed
for your fish, the decomposition of organic matter, and other processes
within your pond. However, photosynthesis only occurs when there
is sunlight. As the sun goes down, plants turn from oxygen producing
organisms to oxygen consuming organisms. Therefore, the more aquatic
plants and algae you have in the pond or body of water, the more
oxygen they will give off during the day and the more they will
consume during the nighttime hours. As the night goes on, the oxygen
levels continue to decrease. The lowest levels of oxygen will be
just before sunlight in the morning before the algae and plants
start producing oxygen again. If your pond has too much plant life,
the oxygen levels can decrease to the point that large fish struggle
to live.

An
algae bloom is a rapid reproduction and spreading of algae when
conditions are right. Algae blooms typically occur during the hot,
sunny, calm part of the summer. When an algae bloom occurs, your
pond can be covered with algae in a very short period of time. The
major problem with an algae bloom is the algae die off. Often even
quicker than the bloom itself, the algae die off can create major
problems. A die off of an algae bloom can be caused by a cloudy
day and lack of sunlight, a cold front, storms, etc.

When
the algae bloom dies off, it adds a large amount of dead organic
matter to your pond. This organic matter is decomposed by microorganisms
at the pond bottom. With the added organic matter load on the pond,
the total amount of decomposition occurring in the pond increases
and the decomposition process uses up oxygen and gives off carbon
dioxide.

This
causes two problems. The first is lack of oxygen. When the oxygen
in the pond is used to decompose the dead algae, it is not available
for fish and other aquatic life. A die off can be so severe that
most of the available oxygen in a pond can be used up in the decomposition
process and your fish and other aquatic life will start to die off.
The larger the organism, the more oxygen it uses. Therefore, your
larger fish that have been in your pond for several years will be
the first to die when oxygen is taken up.

The
second problem with a large die off and increased organic matter
is nutrients. When the algae die off and are decomposed the carbon
dioxide and nutrients are released back into the pond and is available
for the next generation of plant material. The carbon dioxide and
nutrients help to begin the cycle all over again.

In
salt water or brackish water areas, Red Tide can occur. Red Tide
is a naturally occurring phenomenon that can affect brackish and
salt water areas and is a generic name for a harmful algae bloom.
Among the thousands of algae species there are maybe 100 that produce
toxins, which can be ingested by filter feeding shellfish. The right
mix of ocean conditions including low salinity, high nutrient levels,
warm water, and calm seas causes algae to grow rapidly. Red Tide
often occurs when an extended period of sun follows an extended
period of rain. Filter feeding mollusks such as clams, mussels,
and oysters are not safe to eat when harvested in waters affected
by Red Tide because the toxins can build up in these organisms.
This build up is known as bioaccumulation, and over time, the more
toxins an organism is exposed to the more will accumulate in them,
especially in bones and fatty tissues. When the organism is eaten,
those toxins that have bioaccumulated are transferred to the organism
or person eating it. Crustaceans such as crabs, lobsters, and shrimp
as well as fin fish are safe to eat because they do not accumulate
the toxins.

Excessive
algae growth will also limit sunlight from penetrating your pond
and can cause significant thermal stratification, which is temperature
layers throughout the pond. The water that does not receive the
sunlight and warmth cools and becomes more dense. This dense water
sinks and oxygen levels decrease because it is not in contact with
the air. It can also cause turnover in fall and spring, which is
discussed in more detail in the Temperature
Solutions page.

Another
problem with excessive algae growth is irrigation problems. Many
golf courses, farmers, and home owners use ponds as a holding area
for irrigation water. If the pond has excessive algae growth and
is pumped for irrigation purposes, the algae can clog the pump and
filters within the pump, adding many hours of labor to the project.
The algae that passes through the pump will be distributed throughout
the lawn or area irrigated and can be unsightly when it dies off,
as well.

There
is hope for your pond, though. Aeration
can protect your pond and your fish during an algae bloom and die
off. Adding an aeration device, such as a Kasco Pond Aerator or
Aerating Fountain will provide added oxygen to the water and help
buffer the effect of an algae die off. When the algae die and are
being decomposed, the added oxygen allows the decomposition process
to occur properly and also provide oxygen for the fish and other
aquatic organisms. By splashing the water in the air, the aeration
device is not only adding valuable oxygen, it is also helping to
vent gases such as carbon dioxide which is being produced in large
amounts from the decomposition process.

Using
a Pond Aerator or Aerating Fountain will also help prevent an algae
bloom in the first place if it is installed before there is a major
problem. As discussed above, the added oxygen will help the decomposition
process and actually make that process occur quicker. It will also
vent the extra carbon dioxide. This means there will be less available
for the algae to use, which is one of the key components to blue-green
algae problems.

Adding
a Kasco Pond Aerator, Aerating Fountain, or Water Circulator will
also create surface agitation in the pond or body of water. This
is beneficial in a few ways. First, it helps eliminate the still
stagnant water areas and mimics natural wind. As stated above, algae
and algae blooms typically occur in the hot, calm, sunny times of
the year. The agitation at the surface that eliminates the stagnant
areas decreases the areas algae have available to them to thrive.
Just simple movement of the water will help limit the amount of
algae present in the pond. Just think, when's the last time you've
seen a lake that always has ripples or a river covered with algae?
Algae do not like moving water or surface agitation.

Surface
agitation is also beneficial because it helps to mix up the algae
that is already present within the water column. Algae is not able
to sit at the surface of the water and soak up all the sunlight
it needs for photosynthesis and it cannot survive without large
amounts of sunlight. The agitation also helps to destratify the
pond by mixing up the water and limiting the negative effects of
turnover. With water that has been thermally destratified, the pond
is now more hospitable for desired plants and algae species and
creates a better pond ecosystem.

Aeration
can cause a shift in the carbon dioxide levels within the pond and,
in turn, can shift the pH levels causing conditions that are more
favorable for desirable algae to out compete the undesirable blue
green algae.

Finally,
the agitation helps refract some of the sunlight that hits the surface
of the water. This limits the amount of sunlight that can penetrate
the water column. With less sunlight throughout the water column,
algae and other aquatic plants struggle to survive. Some will still
linger, but it will help limit the overpopulation of algae and other
aquatic plants.

Aeration
should not be viewed as a panacea, or silver bullet, but more as
one of the many tools typically used in combination with other methods
of algae control. Added aeration can never hurt a pond (unless start
up of an aerator causes turnover) and most of the time there will
be some type of water quality benefit of added oxygen, not to mention
the increased oxygen levels are great for your fish.

Adding
a Kasco Pond Aerator, Aerating Fountain, or Water Circulator will
help add oxygen and surface agitation to your pond or body of water
and will help with algae problems. However, aeration and water movement
are not cure-all's or silver bullets for algae or water quality
problems. As with many things in life, it is all about balance and
working with other items that produces the best results. There are
several available methods for algae control and prevention, such
as herbicides, bacteria and microbes, chemicals, UV sterilizers,
and other additives like barley straw. Each has a slightly different
way of attacking algae and some may work better in different situations
and applications. However, each is designed to help eliminate and
prevent algae from growing. Some only treat one generation of algae
blooms, others may work for a longer period of time. Either way,
when the algae dies off from natural causes or from one of the above
treatment methods, there will be a large oxygen demand and Kasco
Aeration can help. Also, the added water movement and mixing helps
evenly distribute the treatments used and often makes the treatment
work more effectively.

Dyes
: This is old technology but it can work. Dyes are available in
blue or black, powder or liquid, and act to shade water and reduce
sunlight penetration that feeds algae growth. Aquashade® is
the only EPA registered product for weed and algae prevention, but
most other products work, the just do not have the EPA registration.
A side benefit that has been explored with some success is tinting
the water blue or black to keep predacious birds from harvesting
the fish in your pond because the birds cannot see the fish as easy.
Aeration works great with dyes because it helps mix up the water
and evenly distribute the dye that is added to the water. This method
of treatment does not work well in ponds that are pumped from for
purposes like irrigation or overflow into other ponds, because the
dyes are removed during this process.

Bacteria
and Enzymes : This is a non-chemical approach which
basically involves living organisms feeding off of the excess nutrients
that would otherwise be available for plant growth. The goal with
these products is to reduce organic sediment on the bottom, odor
control, better clarity, and overall better health for the aquatic
environment. Application rates are all over the board and success
is sometimes difficult to measure. Each pond should be looked at
on an individual basis prior to introduction of this product and
it makes the application rates not all that user friendly. A common
brand is Microbe-Lift®.

Ultraviolet
Sterilizers : This product basically works by using
a wavelength of light that will zap planktonic algae. It is very
effective for green water, but will do nothing for filamentous or
erect algae forms because they will not pass through the unit to
be exposed to the light. It should be viewed as a fairly effective
approach for water gardens and fairly
small ponds, but not that effective for larger ponds because of
the costs associated with the larger scale units and applications.
Flow rates are readily available from any of the major manufacturers
of this type of equipment and are measured by micro watts per second
per centimeter squared.

Barley
Straw : Barley straw has been used as a natural alternative
to algaecides for centuries throughout England and Scotland. If
it is to be sold as an algaecide here in the US, it must have an
EPA registration number. Research has suggested that barley straw
can aid in balancing the water quality by lowering the pH and carbonate
hardness of the water, which can control the growth rate of certain
undesirable plants and algae. As the straw degrades in the presence
of water and sunlight, it creates peroxide, which can kill both
filamentous and planktonic algae. It is better at deterring algae
than controlling it once there is already a problem. Application
rates area all over the board and success varies from pond to pond.
A commonly recommended dosage for private ponds (this is how many
get around the EPA registration problem) is 225 pounds of barley
straw per acre of water (about 5 bales) in relatively shallow ponds
of 4-5 feet deep. It is critical that the barley is loosely packed
and that it gets some type of water circulation through the bales.
Kasco aeration and circulation products can add this water movement
and circulation needed for better success. The bales can also act
as a substrate for beneficial bacteria to adhere to and grow. There
are also several products, such as barley straw pellets and barley
straw extract that can be added to your pond instead of the actually
bales, but these products are more expensive.

Ultrasonic
Sound Waves : The basic science behind these units
is fairly sound. They use resonance of ultrasonic waves to kill
algae. A submersed transducer generates ultrasonic waves that shock
the algae and kill the algae by tearing the gas vacuole which allows
them to float. This type of product should not harm your fish. The
problem with this approach is that the cost for the unit is high
and the results are highly variable and marginally successful at
best. The biggest reason behind this is each pond should be looked
at almost as a separate organism with varying water quality. A unit
should then be sized for those conditions. The problem is that this
type of approach does not lend itself to an off the shelf type of
sale and more importantly, drives the cost up to the point where
it is not feasible for many to spend that type of money on a product
without knowing the chances of success.

Skimmers
: There are several types of skimmers available on the market. Skimmers
are usually not feasible in larger ponds or lakes, but work well
in small applications such as water gardens. There are several manufacturers
on the market that make skimmers as part of their pond kits that
include filters, liners, pumps, etc. to create a water garden. The
skimmer collects water and floating plants and sends them through
the attached filter. The filter takes out the plant material and
returns the clean water.

Copper
: Copper is usually the first answer most people get when they bring
up the subject of algae control. Copper is toxic to certain species
of fish within the minnow family as well as salmonids depending
on the dosage and water chemistry. Water with high hardness and
alkalinity buffers copper from being toxic, but also limits its
effectiveness. The most common form of commercially available copper
is granular copper sulfate. Its effectiveness and cost as a broad
spectrum controller of planktonic and filamentous algae has led
to its high usage. Liquid chelated copper products are used to control
a broad range of algae including planktonic, filamentous, and bottom
attached types of algae. Cutrine-Plus® is an example with application
rates from 0.6 to 1.2 gallons per acre-foot of water treated. Consistent
usage of some copper products can lead to bioaccumulation within
the sediments and this approach is on the radar of some regulatory
agencies, so a varied approach is probably the most sensible path
to take.

Fish
: Sterile grass carp have been used to effectively eliminate weeds
within many ponds. Contrary to popular believe, they do not like
to eat filamentous algae or any other types of algae. They are mentioned
here because sometimes they are the cause of a species shift from
rooted aquatic plants to a filamentous and planktonic algae dominated
pond. The easiest way to understand this is to assume that the fish
eat the plants, excrete the waste back into the pond and algae form
as a result. The nitrogen and phosphorus that was in the rooted
plants has not been removed and will manifest itself in algae, which
are not desired by these fish. The questions is , do you want rooted
plants or algae in your pond? Grass carp are not legal in every
state so consult your regulatory agencies prior to stocking them.

Tilapia
have been used to control blue green and filamentous algae in ponds,
but they are a tropical fish and will start to "stress"
when water temperatures drop into the 50's. They are also not legal
in every state and they are what they eat so there is a tendency
for them to be off flavor if they are consuming a fair amount of
plant material as a decent portion of their diet.

Reward®
: This product is a diquat based, powerful herbicide/algaecide commonly
used in natural ponds. It is safe to use according to the label
for all types of algae control in natural ponds, but restrictions
concerning fish harvest apply. This type of treatment works well
with aeration to combat the negative effects of the algae die off.

Peroxides
: Granular based peroxides are super fast acting contact algaecides
for string algae and have been EPA approved within the last few
years. Green Clean® is one of these products that has organic
approval. It is fast acting and bubbles as it oxidizes similar to
medical grade hydrogen peroxide. They byproduct is oxygen and it
is safe for fish at the recommended dosages. The remaining filaments
and cellulose must be taken out of the water or it will settle back
to the bottom of the pond. It is a bit more expensive than some
of the other products, but is amazing for spot treatment and does
not leave any harmful residues. Application rates vary greatly so
it is important to follow the label instructions. As a side benefit,
it works well at cleaning algae off of tanks, aerators, sidewalks,
and even roofs. This type of control method works well in small
applications such as water gardens.

Physically
Removing Algae : This method is used for filamentous
algae and erect algae and is very labor intensive. The benefit to
this approach is that you remove nutrients with the plants which
gets the fertilizers out of the water to temporarily stop the cycle
of growth. People have used dip nets, rakes, pulled by hand, etc.
Whatever works or whoever works because you will not have people
lining up to pull out your algae. The "Algae Monster"
at the top of the page has pulled out a few pounds of filamentous
algae in his day.

Binders
: Aluminum Sulphate (Alum) and forms of alum have been used to clear
up muddy or cloudy water and remove phosphorus. Barraclear®
is a fairly new product with active ingredients of alum, bentonite
clay, and a buffering agent to prevent pH change. It is not an algaecide
or herbicide, but it binds phosphorus to starve the plants. The
amount required is dependant on the phosphorus levels within your
pond so it would be a good idea to get a phosphorus test kit and
consult the label for application rates.

With
all of this said, algae or aquatic plants are not the problem with
the pond, they are simply a symptom. Nutrients
are the main problem with most ponds. The main reason for any algae
or aquatic plant problem is there are too many available nutrients
in the water for the plants to grow and thrive. Grass clippings,
leaves, runoff from fertilized lawns and farm fields or pastures,
animal waste (from geese, ducks, fish, etc.), and organic matter
in the pond (dead aquatic plants) are some of the most common sources
of nutrients in ponds. All of these supply an enormous amount of
nitrogen and phosphorous that aquatic plants and algae need to survive
and thrive. The key to algae and aquatic plant control is controlling
the amount of nutrients entering and existing in the pond.

Limiting
the nutrients is easier said than done. More detailed information
can be seen in the Nutrient Problems
page, but physically blocking nutrients from entering the water
is a first step. The second is helping remove the nutrients that
are already in the pond. This can consist of physically removing
aquatic plants by cutting or raking them out of the water. All the
organic matter in the pond has nutrients in it and when it dies,
it will release those nutrients that will be available for others
in the future. Simply killing the plants doesn't do much for the
overall problem, they need to be removed. The third step is to add
aeration. The extra oxygen, as stated earlier, will help the decomposition
process occur faster and will help limit the amount of nutrients
available. Also, the aeration will help vent some of the gases like
carbon dioxide and others that contain nutrients that plants need
to survive.

Kasco
aeration products, such as the Pond Aerators, Aerating Fountains,
or Water Circulators are one piece of the algae solution, but a
major piece at that. By adding oxygen and surface agitation, a Kasco
aeration product can help prevent a major algae problem, help reduce
the effects of a algae bloom and die off, and over time help limit
and remove the root of the problem, which is too many nutrients
in the water. Kasco aeration may not be a cure-all or a silver bullet
for your algae problem, but it will be a big first step forward
in the fight to either reclaim your existing pond or protect your
new pond.