Taking a departure on dealing with algae problems in aquariums and going to take on pond algae instead. Like their cousins in the aquarium hobby, pond owners also have to deal with pond algae consistently. Only, pond algae is harder to control due to the fact that ponds are normally larger than aquariums and they are mostly outdoors. Which makes it difficult to control the system like you would an indoor aquarium. But nevertheless there are tried and true methods of pond algae control and this guide will list them out.

The kind of pond algae we will be dealing with are classified into three groups:-

  • Microscopic Algae (Greenwater, phytoplankton)
  • Attached-Erect Algae
  • Filamentous Algae
While these pond algae may be different from one another, we are going to tackle them all the same way. They are taking over pond because of two things. Light and the available nutrients in the pond. They get their energy from these two sources. You may think light should be rules out because ponds are outdoors, how are we going to stop light from hitting the pond? By creating shaded spots through the use of floating plants. Floating plants are an excellent way to prevent sunlight from hitting the ponds water. Some ponds even go as far as 50% water coverage with these plants. Aquatic plants also compete with pond scum for available nutrients and that is always a good thing.

On to nutrients. Many things contribute to nutrients in your pond. Including the fish themselves (Fish waste), fish food and any organic material that is slowly rotting. Most ponds will have some amount of sludge buildup over time. This sludge is the organic material mentioned above and it needs to be removed. Rake it all up and what you'll probably see is a dark mud like substance that is a mix of fish waste, detritus and stuff that fell into the pond and rotted away like leaves. Remove as much as you can.

You might want to consider lowering the amount or the frequency of fish feeding. Fishes utilize food very effectively so if you feed them once every two days don't worry, they won't starve.

UV sterilizers have been used with great effectiveness especially against microscopic algae (green water). All you need is an appropriate sized unit with the proper amount of water turnover for this to work. Straws of barley have been known to be pretty effective against most (but not all) types of pond scum. They are sold in bundles of barley straw, barley pellets or a liquid form of barley extract. What happens is they release chemicals that make life difficult for pond algae. The straw is submerged and left in place for a period of time for the process to take place.

Another popular method that you should never consider is the use of algaecides. These are toxic chemicals that are not environmentally friendly. If too much is dosed even your fish will perish. Always opt for natural methods as they are good enough to tackle the problem of pond algae.