If you have an outdoor pond, you know how quickly fresh water can turn murky. Algaecide is an effective temporary fix, but a permanent solution requires a closer look at what causes algae to grow.
As leaves, twigs, and other debris fall into a pond, they rot and release NPK (nitrogen, phosphorus, and potassium). These nutrients are the fundamental ingredients in fertilizer, and the most basic components in plant growth. A surplus of NPK will cause unwanted growth in your pond (algae) and will eventually lead to a cycle called eutrophication.
There are two things you can do to make sure that your pond does not contain excessive nutrients. If your pond is located under trees or bushes, trim the limbs back so that leaves do not fall directly in your pond. Additionally, make sure that runoff that may contain fertilizer is not flowing into your pond.
If you cannot eliminate organic matter from entering your pond and rotting, you can eliminate excessive NPK by using it to your advantage. Many of the nutrients will be used up by allowing more plants to access the water in your pond. Add plants like Water Lillies, Dwarf Cattails, or Umbrella Palms. Moss growing on rocks surrounding your pond may also draw nutrients from the water.
As your plants absorb the excess nutrients, the algae will die and the eutrophication cycle will be stopped.
