How to Get Rid of Algae in Ponds — A Complete Guide for Pond Owners

When it comes to pond maintenance, algae growth is hands down one of the most common and frustrating problems that pond owners face today. Excessive algae growth can easily make your pond water green, clog your filtration system, and potentially even harm the aquatic life in your pond.

The good news is that with intentional maintenance, you can control (and even prevent!) algae growth in your pond.

Why Does Algae Growth Occur in Ponds?

If you're unfamiliar with algae, you might be wondering how they even find their way into your pond in the first place. They're a natural part of the pond ecosystem. With that said, excessive growth can easily disrupt the overall balance of your pond. Algae generally do best in nutrient-rich water, especially when exposed to direct sunlight and poor water circulation.

They receive additional and often excess nutrients from fish waste, uneaten food, decaying plants, and runoff from lawns or gardens. When these additional nutrients mix with sunlight and stagnant water, algae blooms can quickly form.

Common Types of Pond Algae

The three most familiar types of pond algae are green water algae, string algae, and blue-green algae. Green water algae can make the water turn green and murky. It’s the most common type, so you’ve likely seen it before. String algae grow in long, hair-like strands that cling to rocks and plants. Blue-green algae usually form a slimy layer on the water's surface and release harmful toxins.

Identifying the different types of algae in your pond is the first step to effective treatment. Once you know what you’re dealing with, it will be much easier to fight it.

The Best Ways to Get Rid of Pond Algae

1.  Improve Water Circulation with a Fountain or Aerator

Poor water circulation creates stagnant areas where algae thrive. Adding a fountain or aerator increases oxygen levels and prevents algae from forming. Aeration also supports the growth of beneficial bacteria.

Consider installing an aerating pond fountain or a solar pond fountain from Your Pond Pros to keep your water moving and oxygenated at all times, preventing stagnant water and algae overgrowth. If you already have a fountain but you’re still seeing lots of algae, upgrading your fountain pump can do wonders for your pond.

2. Install a UV Clarifier to Control Floating Algae

UV clarifiers use ultraviolet light to target free-floating algae in the water column. The UV light damages the algae’s cell structure, preventing it from multiplying and causing green water.

A UV clarifier is an effective tool for improving water clarity without harming fish or other aquatic organisms. 

3. Use Beneficial Bacteria to Break Down Nutrients

Beneficial bacteria are a natural and effective way to reduce nutrient levels in your pond. They break down organic waste, including fish waste, uneaten food, and decaying plant material, which lowers nutrient levels and makes it harder for algae to grow.

Your Pond Pros offers high-quality beneficial bacteria products that help maintain a balanced pond ecosystem.

4. Add Aquatic Plants to Compete with Algae for Nutrients

Aquatic plants absorb nutrients from the water, which helps starve algae. Floating plants like water lilies provide shade and reduce sunlight exposure, while submerged plants release oxygen and improve water quality.

Plants play a key role in maintaining a balanced pond ecosystem.

5. Treat Algae with Barley Straw

Barley straw is a natural method for controlling algae growth. As barley straw decomposes, it releases compounds that inhibit algae growth without harming fish or aquatic plants.
Barley straw works best when placed in a mesh bag and floated in the pond.

6. Remove Dead Algae and Organic Waste

Once the algae dies off, remove it from the pond. Dead algae sinks to the bottom and contributes to nutrient buildup, which can lead to future algae blooms. Use a skimmer or pond vacuum to remove dead algae and organic debris.

Regular pond maintenance helps prevent nutrient buildup and keeps your pond clear.  Our guide on how to clean pond water explains more about cleaning a pond with fish.

7. Avoid Overfeeding Fish to Prevent Nutrient Buildup

Overfeeding fish leads to uneaten food and excess fish waste, which increases nutrient levels in the water. Feed your fish only what they can consume in a few minutes.

High nutrient levels create the perfect conditions for algae blooms. Reducing fish food and waste helps prevent algae problems before they start.

8. Shade Your Pond to Limit Direct Sunlight

Excessive sunlight encourages algae growth. Adding shade through aquatic plants or a floating fountain helps limit sunlight exposure. Installing a pond fountain also cools the water and improves circulation.

For more tips on managing pond temperatures, check out our guide on how to cool pond water in summer.

How to Prevent Algae Growth Long-Term

Once you’ve treated the algae problem, it's important to take steps to prevent future growth. Regular maintenance and water testing will help you keep nutrient levels under control. Add beneficial bacteria monthly to support a balanced pond ecosystem. Keep the water moving with a fountain or aerator, and trim aquatic plants to prevent excessive plant growth. Removing organic debris regularly and avoiding overfeeding fish will help maintain a healthy pond environment.

FAQs About Algae Control

How Long Does it Take for Beneficial Bacteria to Work?

Beneficial bacteria start working within a few days, but noticeable results can take 1–2 weeks.

Can I Use UV Clarifiers With Fish in the Pond?

Yes, UV clarifiers are safe for fish and other aquatic life.

How Often Should I Use Algaecides?

Algaecides should be used as needed for stubborn algae problems. For the best results, follow the manufacturer’s instructions.

Conclusion

Focus on treatment and prevention to control pond algae and prevent it from overcrowding your space. You can keep your pond clear and healthy by improving circulation, adding beneficial bacteria, and reducing nutrient levels. Products like UV clarifiers, beneficial bacteria, and barley straw provide long-term algae control without harming fish or other aquatic organisms.