Algae control in ponds is probably the commonest problem that pond owners face each year. For a healthy Pond, algae control is a must.  If not treated properly, it can cause nightmares for months altogether for the owner of the pond. Because algae can easily grow out of proportion when nourished with optimum sunlight, water and nitrogenous runoff. In such circumstances, it can clog filter inlets and water pumps, impacts water quality, choke the growth of desirable plant life and ruin the pond beauty.

Causes for Algal Growth

• Algae thrives in ponds that have access to sunlight and receive negligible or no shade.
• Algae breeds in those ponds having large volumes of nitrogen waste in the form of sludge, fertilizers, common pond debris like fallen leaves, invasive pond weeds etc.
• Tap water too facilitates algal bloom.

Symptoms

Though symptoms may vary depending on the type of algae present in a water body, but some of the common symptoms are –

• Floating green scums
• ‘Pea soup' effect is caused when fine algae or Watermeal gets suspended in water
• "Silkweed" or "blanket weed" known as filamentous algae is common pond algae that is known for its dense growth of hair-like strands that float under or on the pond surface.

Chemical Control Method for Pond Algae

There are several herbicides available in the market that can control this pea-soup like algae in ponds. Since they suspend freely in water, you need to use the one that fits best for its eradication. Hence, following is a brief description of herbicides that can be used to control algae in ponds.

• Diquat (Weedtrine-D): Diquat, a contact herbicide helps in controlling top growth of submerged algae. When mixed with endothall or copper chelated compounds, it is most effective in treating other notorious weeds as well.
  
  
• Chelated Copper Compounds (Cutrine plus): They are copper containing organic molecules that remain stable in water. This too is a contact algaecide and is most effective in treating algae.
  
  
• Copper Sulfate: This inorganic compound and a contact herbicide and controls most algae. Its effectiveness depends strongly on the alkalinity of the water. It is not much effective in water with high alkalinity.
  
  
• Endothall (Hydrothol, Aquathol): These again are a contact herbicide which can be procured in a granular form. It gives best results when this herbicide is uniformly applied below or over the surface of the water. Use it in spring when algae growth is fully developed.