Why Is the Water in the Pond Brown?

Why Is the Water in the Pond Brown

Brown pond water is not only a visual problem. It can make life quite difficult for the fish and other animals in your pond. At worst, brown water can be a death sentence for your fish. Algae don’t always have to be the reason for brown water in your pond. It can also be due to feeding your fish that the water turns brown. Brown water doesn’t have to be harmful. This article will help you find out the cause of brown pond water and take the appropriate countermeasures.

Several Causes of Brown Pond Water

The garden pond is a primarily closed ecosystem. If you have created a garden pond and filled it with water for the first time, no ecosystem is yet in place. The ecosystem has to build up first. Therefore, it is pretty standard that the water becomes cloudy after a short time. However, the water then does not turn brown but green. The cause is suspended algae. Once an ecosystem has been built up, the turbidity subsides.

Brown pond water may be due to feeding your fish. Often fish food contains yellowing substances. The colorants are intended to make the feed more attractive to the fish. Especially with pond beginners, it can quickly happen that the meal is overdosed and not eaten by the fish. This favors algae formation, as nutrients get into the water. The yellow substances contained spread in the water and lead to brown coloration. The fish’s excrements can also contribute to a brown coloration of the water and promote the formation of algae. These food scraps and excretions are difficult to biodegrade. You can counteract this problem by using high-quality food and only feeding as much as is eaten.

Brown water can also result from peat getting into the water. This brown coloration is harmless. You should not use peat for your aquatic plants. The pond plants do not need such nutrients.

The brown coloration can also be caused by ordinary water plant soil, dust, pollen, and remains of dead water plants. These causes are also harmless, but they promote the formation of algae. On objects that are directly in the vicinity of your pond, such as patio furniture, mainly made of teak, the stones of the pond’s perimeter or filter covers, dust and dirt will settle over time. If this debris gets into the pond, the water can turn brown.

One problem that can lead to brown water in the pond is leaves falling into the water. Especially in the fall, when the leaves are turning colors, color particles from the leaves affect the color of the pond water.

Errors in Water Supply and Water Changes

Errors in the water supply or water changes can also be responsible for the brown coloration of pond water. If you fill your pond with water from wells or cisterns, this can affect the color of the pond water and the chemistry of your pond. The brown coloration is then caused by dissolved iron and manganese.

Iron and manganese react with oxygen in the air. They initiate oxidation processes that result in brown water. Small amounts of iron and manganese will only dull the appearance of your pond. Over time, sedimentation of these substances occurs. They sink to the bottom, and the water clears on its own.

If large amounts of healthy water enter the pond because you are replacing water or a lot of water has evaporated, the oxygen content of your pond water can drop significantly. This can cause the pond water to tip over and kill your fish. Water from deep wells is harmful, while dug wells or shallow wells is considered harmless.

As a rule of thumb, you should note that the more profound the well you supply water to the pond, the richer the water may be in iron and manganese.

First Brown, Then Green, Then Clear

The pond water is often first brown, then green, and then clear. Brown water may turn green after a few days. Another five to ten days later, it may become evident. The water clears up on its own. The cause is harmless. You do not need to do anything else for the water to clear.

The water’s brown color is caused by leaves or plant parts sinking to the bottom of the pond and decomposing. The water initially turns brown. Bacteria decompose the plant parts and foliage into usable nutrients for aquatic plants. This can lead to a growth spurt for your plants. The algae find lots of nutrients. They spread and turn the water green. If the plants thrive, they produce more oxygen and can contribute to cleaner water.

Eventually, the plants and algae absorb the free nutrients in the pond water. The number of algae is reduced. The pond water becomes clear again.

Simple Causes – Simple Fight

Now you know several causes of brown pond water. Such reasons can be easily avoided or combated:

  • remove contamination of the pond water by leaves, pollen, or insects that have fallen into the pond as soon as possible.
  • do not fill up your pond with water from deep wells or do not use water from deep wells when changing water
  • regularly check the water values with a test set and take the appropriate measures if the values deviate
  • give your fish only as much food as they can eat
  • remove algae regularly, especially on warm summer days
  • shade the pond in summer to counteract the formation of algae

You should also make sure that the fish population is not too large. Remove fish from the pond if they have increased too much. You can offer the excess fish at swap meets.

Regularly check the aquatic plants and the plants on the shore. Remove dead plant parts so that they do not decompose in the pond.

It would help if you also thought about a filter that provides clean water. A biological filter is suitable. A UV filter can clarify the water. It is connected to the pond filter. Intelligent UV filters do not work constantly. A pond pump also does a good job. It provides water movement so that algae and dirt can hardly settle.

Pond Cleaning With the Pond Mud Vacuum Cleaner

To prevent the pond water from turning brown, you should give your pond a beauty treatment with the pond mud vacuum twice a year. You should clean the pond thoroughly in spring when you start the new pond season. Take this opportunity to check your plants for dead plant matter. Divide plants that have grown too large. To prevent plant substrate from washing into the water, you can cover planters with coarse gravel.

Use the pond mud vacuum to suck out the mud and other impurities. It would be best if you also cleaned the walls of your pond well to prevent algae buildup.

In the fall, clean your pond a second time so that you have less work to do in the spring and less sediment settles to the bottom of the pond. You can remove leaves and other debris that have fallen into the pond.

If the water becomes very cloudy in summer, you should also carry out a pond cleaning with the pond mud vacuum cleaner in between or at least replace some of the water.

Sludge Removal With Active Oxygen

To counteract the brown discoloration of the pond water, you can use a sludge remover with active oxygen. A sludge remover is easy to use. The active oxygen drives up impurities. They can then be easily removed with a landing net. This product will not harm plants and fish. During the application of the product, the fish and plants can remain in the pond.

If a layer of mud has already formed in your pond, you can apply the mud remover to the deposits over a wide area. The sludge remover works on any pond. In addition, it enriches the water with oxygen. The biological self-cleaning power of the water is improved. The sludge remover supports the performance of the filter.

Plants for a Biological balance

Plants in your garden pond remove the nutrients from the algae and provide a biological balance. However, you should ensure that the plants do not multiply too much. Water lilies are decorative and provide shade in the summer. They provide good hiding places for fish. However, it does not always have to be water lilies. There are several other plants that make an essential contribution to clean water:

  • Hornwort
  • Musselflower (water lettuce)
  • Milfoil
  • Curly pondweed.

With exotic pond plants, you should pay attention to proper care. Exotic plants can multiply quickly in the summer, but they do not survive the winter in our latitudes. They must then overwinter in an aquarium in a warm place.


The water in your garden pond can turn brown, especially if you have newly created the pond or if there are only a few plants in your pond. Dead plant parts and leaves that have fallen into the pond, uneaten fish food, fish excrement, and water from deep wells with a high iron and manganese content can lead to brown coloration. You should regularly check the water values and remove impurities. You can counteract the brown coloration of the water with suitable water plants, clean with a pond sludge vacuum cleaner, and use pond sludge remover with active oxygen.

Florian Egert

I am Florian Egert, the owner of pondlovers.com. I live with my wife and two children in Germany in a small village in the countryside.

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