Understanding green pond water

Why is my pond water green?

Green water (or ‘Pea Soup’) is caused by an algae bloom suspended in the pond water. This causes the water to turn green in colour, giving it a murky appearance which prevents you from being able to see the bottom of the pond.

There are several factors that can cause excessive growth of algae and although a Green Away treatment will remove algae the causative factors must be addressed to prevent further outbreaks.

Major influencing factors are:

Excess sunlight so you may benefit from adding floating plants – e.g. water lilies and water soldier – to cover up to 50% of the pond surface area or use planting around the pond to create areas of shade across your pond. You do not want to completely shade the pond as this will discourage good plant growth. However, finding a balance could reduce the recurrence of blanket weed.

More nutrients than your existing pond plants can use which stimulates algae growth. Nutrient levels can be controlled by encouraging plenty of healthy fast growing pond plants and regularly removing waste and sludge from the pond.

How to get rid of green pond water

While green water can be a pain, it doesn’t take too much effort to get rid of.

  • Treat your pond with water treatments such as Green Away to clear up your water and protect your fish instantly. You can use our treatment calculator to work out the correct dosage.
  • Test your pond for high nitrates and phosphate levels, treating any issues that impact the water quality.
  • Use Sludge Buster to help remove any dead algae left in your pond.
  • Check all your equipment to make sure it’s working properly – filters, pumps, etc. If you find any issues, carry out any maintenance needed, or replace faulty or broken parts.

Is green pond water bad for fish?

Though you may be concerned about an algae growth affecting your fish, the good news is that green pond water is harmless to fish. If anything, it’s an inconvenience for you, as you’ll be unable to see your fish clearly – which defeats the purpose of having a pond in the first place!

A small amount of green algae in your pond can actually provide beneficial bacteria for fish. In doing so, it can enhance their colour and contribute to their overall health. So long as it’s controlled and not overwhelming the pond, green water won’t negatively impact your fish.

Scroll to Top