Post Treatment FAQs

When will I see results?
Usually plants begin to show signs of weakness or die within two weeks. Signs include discoloration, elongating or wilting. Filamentous algae often turns pale yellow or whitish within three to four days. Planktonic algae disappears in 24 to 48 hours. Dead plants with tough stems and sturdy root systems may remain standing until wind or waves break them up.

What happens to the dead plant material?
Decaying plants and algae usually sink to the bottom after they die. Occasionally, however, plants with weak stems may break loose and float temporarily. Microscopic organisms in the water break down (decompose) plant materials leaving a fine residue od silt which settles to the bottom.

Will my water quality change?
When large masses of vegetation decay, recycling of the plant materials occur. Some nutrients end up in sediment while others enter the water column. Some temporary decrease in dissolved oxygen levels may occur.

How long will control last?
Many weed species can be controlled for an entire season with a properly timed, single treatment. Herbicides do not kill seeds and some do not get into root systems. This can result in a regrowth of plants requiring touch-up later in the season. Algae will generally require treatments three to six weeks apart during the season because of their ability to reproduce rapidly.

Will I have fewer plants next year?
Once well-established, nuisance aquatic plants will typically continue to be a problem each year. Some reduction in weed beds may occur the following year if treatments were made before seed production. A change in dominant species or plant abundance is more likely to occur due to environmental factors such as water clarity, nutrient concentrations and weather factors. Different herbicides may be required.

Do resistant plants establish themselves?
There is some evidence that treating too often, year after year with the same chemicals, may result in the establishment of an unaffected species. This may require changing chemicals, dosage rates, using a combination of chemicals or employing a combination of techniques (aeration, nutrient deactivation, dilution, etc.)

What happens to the chemical that is put into the water?
Products recommended do not remain in the water in their original state for extended periods of time. Chemical and biological actions break down (biodegrade) these compounds into simpler, natural basic compounds. These are recycled within the environment. They do not build up as residues in fish or in the fisn food chain.

What are the common reasons for failure?
Occasional control failures can occur, usually due to one or more of the following reasons:

  • Not reading the product label and following directions.
  • Misidentification of the plant resulting in use of the wrong chemical.
  • Miscalculation of the treatment area resulting in the wrong dosage.
  • Adverse weather conditions (high winds, rain storms, etc.) during or immediately following treatment.
  • Water conditions (high turbidity, low temperatures, etc.) physically of chemically interfering with the herbicidal action.
  • Weed regrowth or appearance of new vegetation.
  • Improper timing or treatment – too early or too late.
  • Rapid water exchange causing chemical dilution.

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