AFS article
Copper is toxic to aquatic animals at concentrations that
depend on the animal species and the water chemistry(i .e.,
pH, hardness and alkalinity).Using Cutrine, (the predecessor t
o Cutrine-Plus,0 .8 times as concentrated S kea and
Simonin( 1979 )reported a 96-h LC50 to fingerling largemouth
bass (Micropterus salmoides) of 6.4 mg copper per
liter at 21.1 øC (methyl orange alkalinity of 53 mg/L) and
0.21 mg/L at 18.3 ø C (methyl orange alkalinity of 95 mg/L)
for fathead minnows (Pimephales promelas). Johnson
(1974), who tested copper sulfate with the marine shrimp
(Penaeus duorarum, P. stylirostris, and P. setiferus),
determinedth at copper sulfate could b e used with juveniles
of these species at levels of 0.5-1.0m g/L as copper sulfate
(alkalinity of 380 mg/L calcium carbonate.).
SRAC
http://srac.tamu.edu/tmppdfs/1239413-SRA...4398261b3e4b767Copper sulfate
(Various trade names)
Copper sulfate is a contact herbicide
primarily used to control
algae. However, it is not effective
for Pithophora control. Copper
can interfere with gill functions
and, if improperly used, can be
toxic to fish and zooplankton.
Fish species such as trout and
koi are particularly sensitive to
copper. However, most fish kills
that occur after copper sulfate
treatment are caused by a massive
algae kill and the subsequent
oxygen depletion.
Copper sulfate is also formulated
as a solution made by dissolving
the crystals in a sulfuric acid
solution. These acidified copper
solutions are registered for aquatic
use and sold under various
trade names (e.g., Copper Cat,
EarthTec, AgriTec, etc.).
The effectiveness and safety of
copper sulfate are determined by
alkalinity and water temperature.
In water with an alkalinity ≤ 50
ppm, the rate of copper sulfate
needed to control algae can be
toxic to fish. Copper treatment at
water alkalinities of ≤ 20 ppm is
extremely risky. In high alkalinity
(≤ 250 ppm) water, copper sulfate
quickly precipitates out and
is not effective for algae control.
The toxicity of copper sulfate to
fish increases as water temperature
increases. Avoid copper sulfate
applications during hot summer
months. (For additional
information on treating with copper
see SRAC Publication No.
410, Calculating Treatments for
Ponds and Tanks.)
Chelated copper
(Cutrine®, Komeen, K-Tea®,
Nautique® and other trade names)
Copper that is held in an organic
complex is known as chelated
copper. Chelated copper formulations
do not readily precipitate in
high alkalinity waters, but stay in
solution and remain active longer
than copper sulfate. Chelated copper
is less corrosive to application
equipment than copper sulfate.
Because it is more soluble, chelated
copper is generally used at
slightly lower rates than copper
sulfate. Chelated copper formulations
are slightly less toxic to fish
than copper sulfate. However, in
waters with low alkalinity (≤ 20
ppm), or in water with an alkalinity
of ≤ 50 ppm that contains
trout, using chelated copper is
extremely risky, particularly during
the summer. Some of the
chelated copper compounds work
on higher plants (e.g., hydrilla,
Najas spp., etc.). Check specific
labels for activity or refer to the
Aquaplant Web site at
http://aquaplant.tamu.edu.
AQUA PLANT
Cutrine Plus, K-Tea, Captain, and Clearigate are all chelated or compound copper herbicides and can be used in a mixture with Reward or Aquathol K. Other chelated or compound copper formulations are available but are not linked to this web site.
Copper Sulfate or "blue stone" is probably the most commonly used algal treatments because of its availability and low cost. Copper sulfate comes in several forms depending on how finely it is ground. Smaller crystals will dissolve easier than larger crystals. In very hard water it is difficult to use copper sulfate because it binds with the calcium, precipitates out of solution, and renders the copper ineffective as an algaecide.
All copper compounds can be toxic to fish if used above labeled rates and can be toxic in soft or acidic waters even at label rates. Before using copper is it best to test the pond water�s alkalinity and adjust copper treatments to alkalinity concentrations. For additional information on using copper sulfate see the SRAC #410 Calculating Treatments for Ponds and Tanks.
To our knowledge Copper Sulfate was the first chemical to be used for algae control. Although Copper Sulfate will kill algae, it is a product that we do not normally recommend.
Copper Sulfate reacts to the hardness of the water that it is being applied to, forming an insoluble salt called copper carbonate. The harder the water being treated the less effective the product is, in very hard waters, Copper Sulfate can have less than a minute of active killing time on the algae.
Even though there are more effective and safer products on the market, the use of Copper Sulfate for algae control is still very common, for two reasons, cost and ease of application.
In looking at a per treatment cost on Copper Sulfate versus the cost of Cutrine-Plus or Captain Algaecide, the Copper Sulfate is less expensive. Looking at it on a per treatment basis is misleading, many times the Copper Sulfate user will spend as much or more in a years time, since the Copper Sulfate will not give the length of control that the chelated copper compounds will.
One of the most common methods for applying Copper Sulfate is to put it in a burlap bag and drag it around the pond or lake in back of a boat, or simply to broadcast it by hand, there is no doubt that Copper Sulfate is easier to apply than a liquid compound that must be diluted and sprayed over the surface of the water.
Copper Sulfate is normally used at a rate of 10 lbs. per surface acre, Copper Sulfate unlike the chelated copper compounds, is very toxic to fish food organisms, and unless you are very careful can even kill fish. Toxicity increases as water hardness decreases.
Long term use of Copper Sulfate can actually lead to severe algae problems, although this must sound strange what happens is that over a period of years the copper carbonate buildup on the bottom of the pond actually will inhibit the growth of rooted bottom vegetation. Once rooted bottom vegetation cannot grow due to the buildup of copper carbonate on the bottom, the nutrients that this vegetation would have tied up is now available to excess algae growth.
We highly recommend that you consider using one of the chelated copper compounds, to avoid any loss of fish or damage to the natural balance of your body of water.
Negative info can’t copy
http://www.chemone.com/default/other/ark_aquafarming_vol_21_no_2_fall_2004.pdfChemistry
http://www.mass.gov/agr/pesticides/aquatic/docs/copper.pdf Pro by fisheries biologist
http://www.bassresource.com/fish_biology/algae_copper.html Copper sulfate was used many years ago for algae control however there was adverse environmental effects of copper build-up in the bottom sediments when this product was used. Since then and over the last 30 years or so, a chelated (chemically locked in) copper compound was formulated called Cutrine-Plus(available in liquid or granular). The product is far superior to copper sulfate in that it provides a longer contact (killing) time due to its stability to work in alkaline waters. It also provides a longer lasting control than copper sulfate with lower copper dosages being used and requires less frequent applications. Research and field usuage have shown a high potential for detrimental environmental effects. In certain waters, copper sulfate is toxic to fish and other organisms. Overuse of this product is common due to its short-term effectiveness. This can result in copper build-up in the sediments leading to a sterile bottom. A sterile bottom will lead to a lack of beneficial bacteria and cause among other things, high algae blooms which in effect, reduces the chances for aquatic plants to grow due to the shading on the bottom caused from the thick algae. When aquatic plant growth diminishes, so can fish growth and survival.
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