Why is my pond water foamy?
Is your water looking a bit more like a cappuccino and less like a pond? It’s common to see white foam on the surface of your pond, especially during the summer months. While it may seem harmless, it could be a sign of underlying issues that could get worse if left untreated.
But not to worry! You can have your pond looking beautiful again in no time. In this guide, we’ll look at the main causes of pond foam as well as steps you can take to remove it from your water.
What causes foam in a pond?
Foamy pond water can be caused by a mix of air, water, and organic pond material. Other causes can include:
- Decay from leaves or other plant material. This can lower the surface tension of the water, leading to foam forming. During warmer months, decomposition rates increase, as does the likelihood of seeing foam on your water’s surface.
- High nutrient levels and algal blooms. Excessive nutrients — like phosphorus and nitrogen — can cause algal blooms, which not only affects water clarity but can also produce foamy water when they die and decompose.
- Detergents and chemicals. If you have recently treated your pond with chemicals or your runoff contains soaps or detergents, these substances can affect the water surface. This, in turn, can lead to excessive foam. We recommend that you always use pond-safe products to avoid such issues.
Foam can occur in any type of pond, but it’s more likely to form in ponds with fish due to increased nutrient levels in the water. Uneaten food, for example, typically contributes to the nutrient load in the pond.
It also can occur at any time of year though it’s more common in warmer months when temperatures rise, or in spring when there is excess pollen and the natural cycle of algae growth begins.
Is pond foam bad for my fish?
In the short term, pond foam shouldn’t pose an immediate threat to your fish. But if not fixed it could cause problems and even make your water toxic, which could prove fatal to your fish’s health.
Foam could also highlight underlying issues related to water conditions which can also harm your fish if left untreated.
How to get rid of foam in your pond
There are several effective products available that act as wetting agents, which alter the surface tension of the bubbles, causing them to burst and scatter the foam. However, it’s essential to address the root cause of the issue as well.
Here are some other steps to keep your pond safe:
1. Carry out water changes to dilute the surfactants
Performing partial water changes can help dilute any pollutants or nutrients that may be contributing to the foam. Aim for a water change of about 10-20% every couple of weeks, especially during peak foam season. Just be cautious not to disturb your pond’s ecosystem by changing too much water at once.
2. Remove excess sludge from the bottom of the pond
Over time, organic matter, such as fallen leaves, dead plants, and fish waste, can settle at the bottom of your pond as sludge.
Use a pond vacuum or cleaning net to carefully remove sludge, taking care not to disturb the beneficial bacteria that help break down organic matter. Aim to perform this task seasonally or at least a couple of times a year to keep it under control.
3. Avoid having too many fish in your pond
Your pond should have a maximum of 60cm of adult fish (i.e. 6 x 10cm fish) per square metre of surface area. Too many fish in your pond can cause more waste, which can increase nutrient levels in the water. This can lead to more algae growth, resulting in foam on the pond surface.
For more information see: How many fish can I have in my pond?
4. Add Sludge Buster to remove dead organic matter
Sludge Buster is a product filled with helpful microorganisms that help break down organic sludge, making it simpler to keep your pond clean and healthy. It helps reduce nutrient levels in the water, which can prevent algae growth — one of the common culprits behind foamy ponds.
5. Improve your pond’s filtration
A good pond filter will help to maintain clean and clear water by trapping debris and removing excess nutrients.
When choosing a filter, consider one that is appropriate for the size of your pond and the volume of water it needs to process. Filters that combine mechanical, biological, and ultraviolet (UV) light sterilization can be particularly effective at reducing algae growth and organic buildup.
You also want to clean your filter every so often to make sure it continues to perform as it should. See our filter maintenance guide for more information.