Dangers of using copper sulfate.
Don’t Use Copper Sulfate!!
When organisms such as algae become a problem in private or commercial fish ponds, copper sulfate treatment provides an inexpensive solution. However, improper application of copper sulfate can create more problems than it solves.
Excessive algae may accumulate in ponds. It may float on the surface and form a scum. Excessive algae can reduce the amount of oxygen in a pond to such an extent that fish die. Parasites such as ich may also harm pond fish.
Copper sulfate kills algae and many fish parasites on contact. It also will kill many weeds that infest a pond. Uniform spraying of a water solution of copper sulfate will guarantee that the copper sulfate spreads evenly across the pond. It is an inexpensive treatment and easy to apply.
Dangers of using copper sulfate. Poisonous to Fish
Excessive application of copper sulfate will kill fish, especially if water is low in alkalinity. If a pond contains less that 50 milligrams of alkaline material per liter, a pond should not be treated with copper sulfate, according to the University of Kentucky College of Agriculture.
If copper sulfate kills a thick mat of algae at once, the decaying vegetation may deprive the pond of oxygen. For dense algal blooms, it is better to apply copper sulfate to the worst spots instead of giving the pond a complete copper sulfate treatment. OR DON’T USE IT PERIOD!
In a pond with algae, copper treatments can cause oxygen concentrations to drop, which may result in fish kills. Pond algae is a major source of oxygen production and by removing it this source of oxygen is also removed. In addition, oxygen will be consumed as the algae decomposes. If you are treating to kill algae, either treat in a series of smaller doses over time or have emergency aeration available.
Copper is also toxic to invertebrates, such as snails, and also most of the zooplankton in a pond (daphnia, rotifers, etc.), so if you are relying on the zooplankton as a food source (i.e. fry ponds), you may not want to use copper.
The use of copper in indoor tanks, where algae and zooplankton are absent, does not present the same problems. However, you still need an accurate measure of the total alkalinity before safe dosages can be determined. Indoor tanks and systems typically have much less organic matter (dirt, detritus) than do outdoor systems usually resulting in the copper remaining in solution longer. To avoid toxicity to fish, water changes are recommended after 4-8 hours of treatment for indoor situations.
In conclusion, copper treatments are very effective for certain situations, and are relatively inexpensive compared with other treatments. Caution must be exercised due to its effects on fish and other life in the water. If your water is low in alkalinity, or if you have a heavy algae bloom and no aeration, copper treatments are not recommended. University of Florida: IFAS Extension
Last Note; Dangers of using copper sulfate.
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.
In review, copper sulfate:
Has short term effectiveness and therefore is often misused and overused. Copper remains in the pond and does not bio-degrade.
Copper sulfate can be toxic to fish and other organisms.
Copper sulfate results in copper build up in pond sediments and creates a sterile bottom in the pond. Besides many important organisms, it kills beneficial bacteria.
Beneficial bacteria such as our all natural, Bio Lake Clear product, breaks down organic matter in the pond including silt, sludge, decaying plants, etc. into harmless chemicals. Beneficial bacteria and algae both feed on nutrients in the water available from the silt, sludge, decomposing plants, fertilizers, etc. By adding beneficial bacteria on a regular basis, you increase the beneficial bacteria colonies and therefore have more bacteria working for you to keep the pond clean, clear and healthy.
We recommend the use of our all-natural beneficial bacteria product, Bio Lake Clear and Ecosocks GC to treat ponds and lakes for algae control and faster organic matter decomposition from silt, sludge and decaying plants & fish.