Use of Aquatic Dyes in Ponds
Forrest Wynne, Aquaculture Extension
Specialist,
Cooperative Extension Program,
Healthy
"plankton blooms (populations of microscopic plants and animals),"
established early in the spring, can turn pond water a green or brown color which
will help inhibit the development of rooted aquatic vegetation and filamentous
algae. Proper pond liming (if
necessary), fertilization, or fish feeding programs will insure the development
of these plankton blooms. If plankton
blooms do not develop after repeated attempts, are not desired, or are not
practical to produce; the use of an aquatic dye may help prevent unwanted plant
growth.
Typically,
dyes would be used in golf course, ornamental, recreational, fish production
and fee fishing ponds. Aquatic dyes are
used to impart a blue or blue-green color to water when added to ponds. Aquatic dyes may also be added to decorative
fountains, industrial cooling towers, and industrial ponds which have little or
no water exchange. Dyes should not be
applied directly to natural bodies of water.
Aquatic dyes are supposed to "shade" the aquatic plants from
sunlight while producing a more aesthetically pleasing color. According to product manufactures and some
researchers, these dyes reduce sunlight penetration into the water column and
reduce plant growth by inhibiting photosynthesis.
Aquashade* is the only aquatic dye
registered with the U.S. Environmental Protection Agency for the use in
commercial aquaculture production ponds.
Water treated with this dye should not be consumed by humans, but is
safe to use for irrigation and swimming following proper dispersal (chlorine
may remove the dye's color) and will not harm livestock. The dye consists of approximately 26% food
dyes (acid blue, 23.63% and acid yellow #23, 2.39%) and 74% water. This product is designed to screen the
red-orange and blue-violet light rays which the plants and algae require for
growth. Aquashade*
is applied from the container to the pond's surface at the rate of 1 mg/l (1 ppm), or 1 gallon of dye to 4 acre feet of water.
According
to the manufacturer, this concentration should prevent the development of
pondweeds, chara, naiads, water milfoil, or
filamentous and blue green algae. A 2
mg/l dye application is recommended to prevent Eurasian milfoil and hydrilla.
Application of dye during the winter or spring may help prevent the
establishment of unwanted plant growth during the summer. This product may be applied to a frozen pond
by pouring the dye onto the ice in a 1 yard diameter circle. The dye will attract sunlight and melt
through the ice and then spread beneath it.
Aquashade* may also be added to
ponds during the summer in an effort to control established plant growth. Dye treatments may remain effective for 4
weeks or longer. The dye is less
effective in pond areas where the depth is less than 2 feet (Aquashade Specimen Label and Fact Sheet, 1992).
Researchers
at
The
cost of Aquashade* is approximately $50.00
per gallon. Cost of the chemical may
restrict applications to smaller ponds where water volumes exchange 10 times or
less during the year. In southern watershed
ponds, dye applications may be most practical in the late summer and early fall
months. These months typically receive
the least rainfall.
*
The Kentucky State University Cooperative Extension Program does not endorse Aquashade or any product.
There is no intention to exclude other similar products.
References
Aquashade Specimen Label and Fact Sheet,
1992. Applied Biochemists, INC.
Boyd,
C. E. 1990. Water Quality in Ponds for Aquaculture.
Boyd, C. E. and M. H. M. Noor. 1982. Aquashade Treatment of
Channel Catfish Ponds. North American Journal of Fisheries Management., 2: 193-196.