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How to Get Rid of Algae in Water Features

Algae is a common problem in water features, such as ponds, waterfalls and fountains. Two main types of algae grow in water features: string algae and plankton algae. Plankton is the algae that grows in the water and turns it a pea-soup green, while string algae looks like green hair and grows along the bottom of your water feature. String algae are usually much easier to get rid of than plankton, due to the different conditions that cause it to grow. String algae grow where there is little water circulation, but plankton grows from an abundance of nutrients in the pond and sunlight.

Get Rid of String Algae

Siphon out or otherwise remove all the water from your pond, waterfall or fountain. Empty the water feature completely.

Sprinkle Kosher or non-iodized salt over the bottom and sides of the water feature. Be sure to cover all the surfaces where the string algae are growing.

Allow the salt to remain on the water feature’s surfaces for about three or four days. Then, scrub the surfaces with a medium-bristle brush.

Rinse the water feature thoroughly to remove all the salt. Refill with clean water.

Get Rid of Plankton Algae

Clean your water feature to remove all debris, especially any fallen leaves in the water. You can use a net or pond vacuum, depending on the type of water feature you’re cleaning.

Empty all the water from the fountain, waterfall or small garden pond. Scrub away any algae clinging to the sides or bottom of the water feature and refill it with clean water.

Add beneficial bacteria to the water so that the bacteria can help to process fish wastes and other nutrients in the water that algae consume. Many beneficial bacteria products exist for water features, found at most aquarium or garden stores.

Move your water feature into a shaded area to reduce the amount of sunlight exposure. If the plankton is growing in a pond, add some aquatic plants to shade the pond’s surface area.


If you have a pond water feature, you can also add plants, filter media, a biological filter, an aerator and rocks to help reduce the excess nutrients in the water that enable plankton to grow.

Many plankton algae-killing products exist for water features, but they usually provide only a temporary fix and some are not safe for ponds containing fish or plants. Even if you use a quick-fix algae killer, be sure to reduce the sunlight exposure and excess nutrient levels in the water to prevent the plankton from returning.


If you’re cleaning out string algae from a pond with fish and plants, be sure to remove them before emptying the water.

Don’t overfeed your fish in your pond, because the excess nutrients from uneaten fish food can cause plankton to thrive.

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