Algae in Fountains

• Blanket algae grows to cover the surface of fountains.Jupiterimages/Photos.com/Getty Images
  
  Algae can appear in any unfiltered water and is an essential part of sea or pond life. In fountains however, it can be a nuisance, discoloring the water or creating a weave of plant matter across the surface; ruining the aesthetic value of the fountain. There are many species of algae, but they all come down to two distinct groups: string and planktonic.
  
  

Planktonic Algae

• The algae that discolors the water in fountains, turning it brown, green or blue-green, is known as planktonic algae. There are many different species of planktonic algae, which are tiny microbes of plant life rather than a standard plant, and the precise collection of species present in any "bloom" of planktonic algae depends on the temperature and nutrient content of the water in the fountain.
  
  

String Algae

• String algae is also commonly known as "blanket weed," due to its ability to create a blanket-like sheet of plant matter across the surface of any water on which it grows. Like planktonic algae, string algae is not one species of algae; instead, the group consists of many different species that act in a similar manner to one another. The most common species of string algae in fountains are the Cladophora, Spirogyra and Oedogonium families.
  
  

Algae Prevention

• If left to its own devices, algae will grow in any water where there is sufficient light and nutrient content. To keep your fountain clear of algae, change the water regularly and use a filter in the fountain pump to remove small deposits as they appear. You can also use chemicals to prevent algae growth and keep your fountain crystal clear, but this is dangerous if pets and small children are around.