A water feature such as a garden pond or water fountain can be an important element in your landscape. Water features may be used to create soothing sounds, or to support fish and aquatic plants. Algae can sometimes invade your water feature, turning the water into a murky mess. Algae may also emit a bad smell. Take steps to get rid of algae in your water features and restore the water's fresh appearance.
Empty out the water feature and clean it. This option is best for water features such as fountains that do not have aquatic animals or ornamental water plants. Wipe down the interior of the feature with a sponge dipped in vinegar to kill any algae deposits. Rinse and allow to dry thoroughly. Refill the water feature with fresh water and resume use.
Kill algae in large water features using potassium permanganate, a natural algicide. This fish- and plant-safe technique is best for large water features like garden ponds. Multiply the pond's surface acres by its depth, then multiply by 5.4. The result is the number of pounds of permanganate needed to create a water concentration of two parts per million (PPM). Empty the potassium permanganate into the water.
Use a chemical algicide, available from a pond supply store. Algicide is ideal for extreme algae infestations. Pour the algicide into the water feature in accordance with the product's instructions, as product potency fluctuates among manufacturers.
Keep the algae from regrowing. Add a blue pond dye to limit the amount of sunlight in the water and discourage regrowth. Alternatively, add more ornamental plants such as duckweed or pond lilies to the water feature. The ornamental plants will consume excess nutrients in the water, starving any existing algae and discouraging future algae infestations.
The existence of excess nutrients in the water is a common cause for algae blooms. If you own a pond, make sure there is no water runoff into the pond. If you run a fountain or similar feature, remove debris, leaves and other organic objects that may fall into the water feature.