Algae thrives on excess nutrient and sunlight. Limiting either or preferrably both will help control algae your the water garden.
- Check your fish load. You should only have 1″ of fish for every 10 gallons of water in your pond.
- Limit feedings. The less food you give the fish the less nutrient they will put back into the water.
- Use a good number and mix of aquatic plants to absorb excess nutrients from the pond water to starve out the algae.
- Use floating plants (water lilies, lotus, water lettuce, etc) to shade the water to limit the amount of sunlight entering the pond.