Pond sludge is completely natural, important and occurs in every garden body of water - but over time it can develop into rot. This affects the water quality and the aquatic plants, as well as the pond inhabitants. For this reason, it is important to remove it regularly. There are basically two options for this and the question of disposal only plays a role in one variant.
Pond mud
Pond sludge is created through completely natural decomposition processes in the water. Leftover food, leaves, plant parts and fish excretions form the basis. Microorganisms decompose these and form the muddy residue on the ground. This is completely normal and helps to maintain the water quality in balance.
But if the layer of mud becomes very thick, it definitely poses a problem. On the one hand, it can cause rot to form in it, which is noticeable through rising gas bubbles and a putrid smell. On the other hand, the pond sludge is rich in nutrients. If it is stirred up in the water by fish, frogs, toads, amphibians or other movements, these nutrients are redistributed in the water. This can result in increased algae formation and ultimately cause the water to “tip over”. This in turn leads to the death of aquatic life and plants.
Tip:
Pond sludge must be removed regularly and at least once a year.
Time
The pond sludge can be removed in spring or autumn. The measure is necessary at the latest when gas bubbles rise. It should be remembered that if the pond is frozen, the gases can no longer escape. It can therefore make sense to remove the mud again in the autumn, especially for fish that overwinter in the pond.
Prevention
To prevent excessive pond sludge from forming or to delay its formation, preventive measures can be taken:
- Remove larger dirt, such as fallen leaves, quickly
- Adapted feeding
- Removing wilting plants
- Use filters
- Fishing algae
In this way, less organic material is available for the sludge to form. It will still occur just from fish droppings and sunken plant parts, but to a lesser extent.
Tip:
Sludge formation can also be prevented by not creating the garden pond near trees or deciduous plants.
Mechanical removal
One way to remove pond sludge is to remove it mechanically by:
- Suction
- Skimming
- Dry removal
Suction
The most widely used measure to remove pond sludge so far is vacuuming. A special pond sludge vacuum cleaner can be used for this. A purchase is not always necessary, as some hardware stores and garden centers also allow you to rent such a device. In the long term, however, it is usually more cost-effective to invest once in a pond sludge vacuum cleaner.
The vacuum cleaner removes the substrate mechanically. It can be used easily and specifically - but it also has disadvantages. Suction not only removes the sludge, but also useful bacteria and other microorganisms that are required for the decomposition of organic components. This initially affects the water quality. This also applies to the other options for mechanically removing pond sludge.
Skimming
The pond sludge can also be removed without any electrical equipment by removing it by hand with a very fine-mesh landing net, a bucket or similar container. The disadvantages of this method include:
- A lot of mud and nutrients are stirred up and distributed in the water
- Very complex and tiring, especially with large ponds
- Requires great care not to remove any aquatic creatures
In addition, the microorganisms are removed to a large extent.
Dry removal
If the fish do not overwinter in the pond, the water can be drained in the fall. After a few days, the pond sludge will dry and can then be removed comparatively easily. The disadvantage of this method is that the pond has to be completely “run in” again in the spring. Water purifiers from specialist retailers can help you quickly restore appropriate water quality. However, this variant is only recommended for smaller ponds.
Biological removal
Biological removal of pond sludge is faster, easier and requires significantly less effort. Special pond sludge removers can be found in specialist shops for this purpose. They are offered in the form of powder or ready-to-use solutions and break down the sludge over days and weeks. The duration of the process depends on the thickness of the mud layer. If a lot of deposits have already accumulated, the application may need to be repeated.
The advantage here is that the agent is simply distributed in the water and neither the laborious removal of the pond sludge nor its subsequent disposal is required. In addition, the beneficial organisms are not removed. However, the water turns milky white when used and the time until it is successfully dissolved cannot always be estimated precisely. This variant is therefore only recommended if there is no acute and threatening siltation of the water.
Tip:
Pond sludge remover can also be used to prevent excessive sludge formation, but must be used regularly as recommended by the manufacturer.
Disposal
Sludge from larger garden ponds in particular seems difficult to dispose of at first because of the amount alone. If it has been vacuumed or skimmed wet, it is also very heavy and can therefore only be moved in small quantities. However, disposal only appears to be a problem at first. Pond sludge is a very nutrient-rich, natural fertilizer. It consists of remains of plants and food, fish droppings and is already decomposed. In principle it is very similar to compost soil. It can therefore be added to the compost or used directly as fertilizer and does not have to be thrown away.
Caution is only necessary with pond sludge that is already showing signs of rot. With this it is advisable to first let it dry outside the pond and then add it to the compost. In this way, potentially harmful substances are reduced and the risk of mold is reduced. If there is no need for pond sludge as fertilizer and there is no compost available, the nutrient-rich sludge as well as algae and other organic substances can be disposed of with residual waste or organic waste.
Tip:
Pond sludge has a relatively strong odor, which is why appropriate clothing should be worn and the skin should be protected when removing and disposing of it.
