How to Protect a Pond From Algae

Ornamental ponds and water gardens are restful, beautiful, soothing and inviting. However, an excess presence of algae in a pond can turn it into an ugly green mess. It not only ruins the appearance of your pond, but may also harm the plants and fish you keep there. Fortunately, you can protect your pond from algae by using a few simple techniques.

Difficulty: Easy

Instructions

Understand the Process of Algae Formation

1. Understand that there are two types of pond algae: unicellular and filamentous. An excess amount of unicellular algae turns the water green, while having an excess of filamentous algae clogs filters and harms plants in your pond.

2. Know that algae thrive in warm, deoxygenated water. Algae also need nutrients to grow. These nutrients can come from fish, decaying plants and high presence of nitrites, nitrates or phosphates from fertilizers.

3. Learn the chemistry of your pond by using testing kits. You should test regularly the temperature and for the presence of high levels of nitrates or other elements in the water. When you know what algae feed on in your pond, you can take corrective measures.

Protect Your Pond

4. Change the water in the pond if the water test shows high levels of nitrates or other unfavorable elements. First, remove debris at the bottom of the pond. Make sure that the pump and filter are clean and then take out about a third of the water in the pond. Refill with one-third fresh water. Note that if there is chlorine in the fresh water then you need to dechlorinate the water.

5. Install a combination of an ultraviolet light clarifier and a biological filter. The UV clarifier clears the water of algae and eliminates other harmful bacteria while the biological filter cleans the water and removes the dead algae. If you keep fish in the pond then a biological filter is important to ensure healthy fish.

6. Aerate the water in the pond by installing a waterfall, fountain or aerator. This releases the carbon dioxide in the water and helps the water to absorb more oxygen.

7. Get water lilies or water hyacinths to keep your pond cool and shaded. Shading is important during the summer because the heat and the sunlight can increase the water temperature, which in turn can cause an increase in algae growth. You can also shade your pond by building an arbor, which can block some of the sunlight.

8. Control the number of fish you keep in your pond. In addition, also limit the amount of food you feed the fish. Taking these measures ensures that excess nutrients do not accumulate in the pond.

9. Keep the surface of the pond clean by removing any fallen leaves or other debris. Use a rake to remove any debris.

Tips & Warnings

• It is important to keep filters clean to ensure proper filtration.
• When choosing a combination UV clarifier and a biological filter system, it is important to get the right size for your pond so you need to know the volume of your pond.