How to Manage Green Water and String Algae in Your New Pond

Struggling with green pond water or string algae in your new pond? You’re not alone! Many new pond owners face the challenge of algae growth shortly after setting up their ponds.

In this guide, I’ll explain why your pond water turns green, why string algae appears, and how to manage it without resorting to harmful chemicals. With a little patience, your pond can naturally balance itself.

If you’d prefer to watch a video, watch the video I made on the topic below.

Why Does Algae Grow in New Ponds?

If your pond water has turned green or if you’re seeing string algae just a few months after building your pond, it’s completely normal. Algae thrives in new ponds because they are rich in nutrients, especially if there’s debris or soil left on rocks and pebbles, during the construction.

Even when you add pond plants they are often grown in nutrient rich substates. Plant growers want their plants to grow quickly so they can sell them fast!

These nutrients are perfect for algae to flourish, especially before your aquatic plants have developed strong root systems.

Algae, particularly green water algae and string algae, grow quickly in new ponds because they take advantage of the available nutrients much faster than your plants can.

But don’t worry—this is a natural part of your pond’s ecosystem finding its balance.

It’s not only plants that can process nutrients, beneficial bacteria will also process nitrogen and phosphate. Again, in a new pond the bacteria take time to establish.

How to Prevent and Manage Algae in Ponds

Patience is Key

The best way to manage algae in your pond is to give it time to find its natural balance. Every pond is different, and the time it takes to clear up can vary.

Some ponds may balance in a few weeks, while others might take a few months. Thoroughly washing rocks and pebbles before adding them to your pond can reduce algae growth, but even with the best preparation, some algae is inevitable.

It’s also important to remember that if the filtration is inadequate you may never achieve clear water. If you are unsure if the filtration is adequate read my article on pond filtration and understanding the importance of good pond filtration.

Natural Algae Control

Instead of using chemicals, consider letting the algae run its course. Algae, while unsightly, provides food for fish, shrimp, tadpoles, and other beneficial organisms in your pond.

Using algaecides, copper ionizers, or even hydrogen peroxide can kill algae but also harm the beneficial bacteria and microorganisms that are crucial for a healthy pond ecosystem.

If you want to you can manually remove the algae with a net or pond vac. When you remove the algae you remove the nutrients it is using to grow.

Use Diatoms for a Healthy Pond Ecosystem

Not all algae are harmful. Diatoms, a type of beneficial algae, form the base of the food chain in your pond.

Adding diatoms can help speed up the process of establishing a balanced ecosystem.

Products like diatomix or nualgi can be very effective. They might seem pricey, but they’re economical if used in small, recommended doses.

Consider Bacteria Blends

While bacteria blends may sometimes act as a placebo, they won’t harm your pond and can help maintain a balanced ecosystem.

The bacteria occur naturally, but I must admit even I feel better adding something rather than sitting back and waiting.

A healthy population of diatoms and beneficial bacteria will help break down phosphates—one of the main nutrients that feed ugly algae like string algae.

Conclusion

Dealing with green pond water or string algae can be frustrating, but it’s a normal part of the pond’s development.

Instead of panicking, give your pond the time it needs to balance itself naturally. Avoid harsh chemicals and focus on building a healthy ecosystem with beneficial algae, bacteria and micro-organisms.

With patience, your pond will clear up, leaving you with a beautiful, thriving aquatic environment.