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Stock Tank Algae Control
Michael Fisher, Area Extension Agent - Golden Plains Area
Date:
6/10/2011
Questions? Contact
Me
About this time of year I begin getting calls regarding how to
control algae growth in stock tanks. Algae growth is a fact of summer for
livestock water tanks in Eastern Colorado. Before talking about controlling it,
let’s talk about trying to limit some of the algae growth.
There are some basic essentials that algae require to grow in a
stock tank. The most obvious is water and we can’t do much about that.
Next, warm temperatures and sunlight dramatically promote algae growth. Some
producers will build shade over their stock tanks to help with this issue.
However, that creates an added expense and may cause problems with livestock
trying to utilize that shade on hot days. Finally, algae needs some form of
nutrients to sustain itself. This can come from livestock slobbers, animals
urinating or defecating in a tank, and debris being blown into the tank. Part
of this is unpreventable, but fencing or rails can be utilized to prevent
livestock from entering a stock tank and introducing nutrients. If using rails,
make certain they are positioned low enough that a cow can’t slip
underneath the rail.
Once you have an algae problem in your stock tank,
there are some treatment methods that you can utilize. There are numerous
commercial products on the market. However, a generic approach to chemical
treatment is often times cheaper. (Remember that chemical treatments may change
the taste of the water for a period of time. Also, these need to be mixed
thoroughly within the tank for a few minutes before livestock are allowed
access. Don’t just dump it in one part of the tank and drive
off.)
Chlorine Bleach: Sodium hypochlorite (5.25%), which is what
many of the standard laundry bleaches (only use unscented) are made of, can be
effective. You will need to add 2 to 3 ounces of the 5.25% sodium hypochlorite
for each 100 gallons of tank capacity. Be sure to mix the tank water well after
adding the bleach. This should be repeatedly weekly. When temperatures are
abnormally hot and when a lot of organic material exists in the tank, the
sodium hypochlorite will dissipate more rapidly and may require multiple
treatments per week.
Copper Sulfate: Copper sulfate is a popular
algae control and is found in many of the commercial products. It will often
come in a crystal form and needs to be dissolved in warm to hot water before
making the treatment. Typically, 1.5 teaspoons should be dissolved in 4.5
ounces of water for each 1000 gallons of tank capacity that will be treated.
This mixture is then poured throughout the tank. Treatment should be repeated
in two to four weeks, depending on algae growth. Algae killed using this method
should be removed from the tank and hauled out of the grazing area, as it may
contain very high copper & sulfur levels. The use of copper sulfate is not
recommended when sheep will be consuming the water, as sheep have a low
tolerance for copper and this treatment may be toxic to more copper sensitive
sheep. Another important note is that copper sulfate can increase the rate of
deterioration of metal tanks and pipes.
Zinc Sulfate: Zinc
sulfate is another chemical treatment. Again, the material needs to be
dissolved in warm to hot water before being added to the tank. In the case of
zinc sulfate, dissolve one cup in one gallon of water. Then thoroughly mix into
the tank ½ cup of the solution for every 100 gallons of tank capacity.
Repeat as needed.
Biological Control: In these times of consumer
concerns over what is in their meat, more and more producers are turning to
herbivore consuming aquatic life to maintain reduced algae levels in stock
tanks, as opposed to chemical treatments. One of the more common resources is
the goldfish. It will take 4 to 6 goldfish for every 100 gallons of tank
capacity. Other aquarium species can be more expensive ($3 to $6 each) but
still effective. Some of these are the Black Mollies, Otocinclus Catfish, and
my personal favorite the plecostomus. Some varieties of plecos, like the
Trinidad Pleco, can grow to near a foot in length and spend a surprising amount
of their time foraging.
While these biological control techniques do
offer a good marketing statement for those selling in all natural programs,
they still create issues. First, you are trading algae for fish feces in your
tank. Secondly, fishing predators (raccoons, cats, birds, etc.) may become
attracted to your stock tank & treatment technique. Thirdly, if you are
changing pastures throughout the grazing season you will need to move the fish.
Finally, you will need to have a plan for caring for the fish during the winter
months.