Controlling Algae in Your Water Garden

Not all algae blooms are harmful, but those that are can be toxic for plants, animals and humans alike. Even when the unwelcome green blooms are harmless, they can raise a stink, turn into an eyesore and obscure and kill colorful fishes by hogging up their oxygen. The good news is that it does not take a lot to control the green menace. Continue reading to know how…

Keeping a check on the algae problem

While it is neither beneficial nor possible to completely eliminate algae from a water garden or pond, there are a few things you can do to ensure that the messy green does not overshadow all else.


  • Don’t overfeed the fish because this leaves too many nutrients behind to feed the algae.
  • Don’t go overboard with the number of fishes in the water garden.
  • Keep your pond free of organic debris, which turns into algae food upon decomposition.
  • Keep the filters clean of decomposing organic matter, including foliage.
  • Ensure that your water garden has less than ¼th inch of sludge at the bottom.
  • Having a circulation system in place that keeps the water moving and oxygenated even at the lower levels.
  • Use bacterial and enzymatic additives to improve water quality.

Going natural with algae control

Plants to the rescue: Use floating plants (40-60% water surface coverage) to starve algae of light, oxygen and food; shallow water plants to clear excess nutrients from the water and submerged plants to increase oxygenation at the lower levels.

No sunlight, no food: The use of pond dye limits the amount of light that penetrates to the bottom of the water garden. Since algae need sunlight to bloom, a water dye helps to limit their growth.

Technology against aggressive algae!

  1. An ultraviolet water sterilizer/clarifier offers one of the most effective ways to kill free-floating green algae cells. Ultraviolet light degrades the algal cell membrane and stops algae from reproducing. Since there can be as many as 5 million of these green-blue cells in every square millimeter of water, you are talking about a significant amount of killing here and a notable reduction in the amount of green slime.
  2. A pond ionizer is another device that gets the job done effectively and safely. The device releases just the right amount of minerals in the water, which help the plants to thrive and kill the algae.

UV water sterilizers don’t work against filamentous/stringy algae that grow on waterfalls and rocks. You will have to either scrub off this green problem or remove it by using a high-pressure hose or a net.

Chemicals and good ol’ elbow grease!

You will find both natural and chemical algaecides in the market. On the natural front, barley straw extract and copper laced algaecides are among the most effective. In addition to these, you can also use water clarifying chemical treatments that cause the algal cells to clump together and settle at the bottom. You can, then, use a skimmer net or pond vacuum to get the green clumps out.

There is simply no way to completely rid your water garden of algae; not to mention that some of these green suckers actually help the ecosystem of the water body. But, you sure can stop them from turning into a problem by maintaining a balanced environment.

While algaecides, filters and advanced algae killing devices offer quick reprieve from the green, slimy menace, only Mother Nature can provide a long-lasting and permanent solution. So, consider a natural plant filter system to keep your water garden full of the right kind of green!