Prefer to read?

Here’s what Ash explains in this video…

Green water is one of the most common pond problems, caused by microscopic algae that thrive in nutrient-rich environments. While it’s not harmful to fish, it can quickly make your pond unsightly and reduce visibility. Here’s a comprehensive guide to clearing and preventing green water in your pond.

1. What Causes Green Water?

Green water is caused by millions of tiny algae spores that multiply rapidly when there are excess nutrients in the pond. These nutrients come from:

• Fish waste and uneaten fish food.
• Sludge buildup: Decaying leaves, twigs, and debris that settle at the bottom of the pond.
• High nutrient levels: More fish and debris mean more sludge and algae growth.

If your pond is surrounded by trees or bushes, leaves falling into the water can contribute heavily to nutrient buildup. Using preventative measures to reduce sludge is key to stopping algae growth.

2. How to Treat Green Water

The simplest and most effective solution for green water is bacteria-based treatments, which target algae spores and remove them from the water.

• Pond Klear: Ideal for smaller ponds (up to 3,000–4,000 litres) that are just starting to turn green.
• Pond Klear Xtra: A stronger solution for larger ponds or those with severe algae problems.

How it works: The bacteria in these products clump the microscopic algae spores together, allowing the pond pump and filter to remove them effectively. This process also targets the nutrients that feed algae, helping to clear the water and prevent further growth.

3. Preventing Green Water with Plants

Plants are nature’s solution to controlling green water. By absorbing excess nutrients, plants deprive algae of their food source.

• Oxygenating plants, water lilies, and other aquatic plants are ideal for maintaining a healthy pond ecosystem.
• Goldfish ponds benefit greatly from plants, as goldfish do not eat them excessively.
• Koi ponds are trickier, as koi often see plants as food and will eat them quickly.

For koi ponds, alternative methods like regular treatments and filtration are essential.

4. Invest in a Good Filtration System and UV Light

A strong pond filter with UV lights is one of the best long-term solutions for preventing green water. Here’s how it helps:

• Circulates the water: Prevents stagnant water where algae thrive.
• UV light exposure: Kills algae spores as water flows through the filter.

To improve oxygen levels and water movement further, consider adding:

• Water features like fountains or waterfalls.
• Air stones to increase oxygenation and promote healthy water circulation.

5. Ongoing Maintenance

Once your pond is clear, regular maintenance is key to preventing green water from returning:

• Use treatments like Pond Klear Xtra weekly: This helps control nutrient levels and stops algae growth.
• Clean your pond filter regularly to remove trapped algae and debris.
• Skim leaves and debris off the surface to reduce sludge buildup.

For ponds that have been neglected for a while or turned very green, consistent treatment and cleaning will restore clarity over time.

By using the right treatments, maintaining good water movement, and incorporating plants, you can clear green water and keep your pond healthy and clear all year round. For more tips, like this video, subscribe to our channel, or drop us a comment – we’re always happy to help!