How to Clean Out Algae in a Preformed Small Pond

All garden ponds will grow some algae.

Algae commonly occur in newly established preformed ponds. The unsightly green water is generally due to an unbalanced condition in the water. Draining the pond and starting over will basically extend the problem, as the algae will grow back. Excess nutrient levels in the water combined with ample sunlight provide the perfect environment for algae growth. Reducing the overall nutrient level or decreasing the amount of sunlight reaching the surface will minimize the algae growth.

Things You'll Need

• Broadleaf water plants (floating water lilies)
• Snails
• Small bag of straw
• Beneficial bacteria supplement
• Mechanical or biological filter and pump

Instructions

1. Plant broadleaf water plants such as floating water lilies. The large leaves will shade the water surface and the floating roots will consume excess nutrients decreasing the algae bloom.

2. Release some water snails into the small preformed pond. The bottom feeding snails will eat waste material from the pond bottom and keep it cleaner.

3. Set a small bag of straw into the water at the ponds edge. The straw will produce beneficial bacteria that will begin to consume the growing algae.

4. Add a beneficial bacteria supplement to the water. Follow the manufactures labeling as to amount of dosage for your size of small pond. The bacteria will react with the algae; decreasing the overall bloom.

5. Install a mechanical or biological filter and pump system to circulate the pond water as a last resort to balancing and cleaning out the pond water. The filters will remove the algae and the food source.

Tips & Warnings

• All ponds of all sizes will experience a large algae bloom during early spring. This is normal for all healthy bodies of pond water.

• Never drain the small preformed pond and add city treated water. The chemicals in municipal water will kill all aquatic life in the pond and most plants.

References

• Oregon State University: Backyard Ponds and Water Features
• Pond Solutions.com: Algae and Weed Control Information
• Practical Water Garden Solutions: Solve Pond Algae Problems