How To Remove And Combat Diatoms In The Pond

Diatoms can appear after a very short time, due to the silicates (silicic acid) present in the water, diatoms form and multiply quite quickly. An undesirable and annoying matter for all pond owners.

Diatom Algae A Natural Cleaner - Clean India Journal

However, this type of algae can also be a sign of too bad conditions in the pond, for example, if the bottom is increasingly silted, or the filter. In itself, this form of algae is not a threat to the plants, decorative objects and the pond, they do not destroy anything and plants do not suffer from this form of algae. Nevertheless, they multiply rapidly and thus form unsightly slime, which disturbs the appearance and the pond becomes more and more slimy. Which is a great disaster for a pond owner who always cares for his pond and wants to enjoy it.

The origin

Diatoms live in a shell, this shell consists of two parts and these parts are normally connected. If the algae multiply, the parts of the housing divide, now each missing part of the housing is newly formed, thus their multiplication is fast and is already clearly visible in only a few weeks. They prefer to settle on the edges and the bottom of the pond, but the more space they occupy, the more they spread to stones, decorations and plants. They prefer to live in areas that are not well lit or not lit at all, this is their habitat and they can spread to their hearts content.

Recognizing diatoms

Some pond owners find it difficult to tell the difference between diatoms and smear algae, although smear algae are bacteria and belong to the cyanophyceae. Whereas smear algae have a gelatinous structure, diatoms are free of gelatinous structures, they feel something like sandpaper and thus have a rough surface.

Characteristics of diatoms:

Spotty or flat coatings on plants.
The stains can be easily removed, for example with a sponge
Brown residues on the skin when run over with the finders
The algae have a rough surface

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Often they are among the first settlers of a pond – the diatoms. However, it is not necessary to fight them right away, as they usually disappear on their own and as quickly as they came. Before it is necessary to combat the algae, it depends on the extent to which the diatoms have developed and how far they have spread over a period of time. However, if the problem lasts longer and becomes increasingly larger, there is no way around its elimination.
The elimination requires time and care, but to have a beautiful and handsome pond, the effort is worth it. In this case, all affected areas and plants should be wiped. Apparently, the diatoms are then gone, but unfortunately the impression is deceiving, the life forms are still present and must be fundamentally combated.

As the name suggests, diatoms live on silicic acid (silicates), which is their nutrient to be able to multiply and to take over the pond with their slimy consistency. So this is the point to start from. Especially hard water is rich in silicic acid, a paradise for diatoms. In order to tackle the problem here, the problem must be hit at the core and that is the water. Here, osmosis water should be used if possible. Another but additional step is to set the pH value in the pond low. The diatoms will not find nutrients with these measures.

Another possibility, which can also be used additionally, is lighting. The algae love places that are in the dark and shaded areas, there they like to collect and multiply rapidly. Therefore, sufficient lighting in and around the pond, is recommended. Even after changing the water and pH, lighting should be done, thus excluding more and more factors that are food sources for diatoms.
Fighting diatoms with other pond inhabitants
The measures to fight the algae are visibly time-consuming and require patience. Another possibility is to get rid of diatoms with other animals in the pond. Snails are particularly productive here, as they feed on the algae and are always hungry. In addition to snails, crayfish are also a good choice. Crayfish and snails can also be kept together and additionally ensure that the balance in a pond is maintained. So-called sucking catfish such as Farnowella, Otocinclus and Ancistrus can also help, as they also feed on diatoms.

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If the control should take place without other pond inhabitants, the pond must be cleaned completely in any case:

  • Cleaning the pond, plants and other decorative objects.
  • An important main feature is the bottom of the pond, it should be carefully cleaned, because diatoms feel very comfortable there. The bottom is located in the shadow area and good lighting is usually not given there.
  • After cleaning, use the water recommended in the article.
  • Lower the pH value existing in the pond.
  • Light the pond well. Outdoor lighting is not necessarily enough, so good indoor lighting in the pond should also be provided.

If these measures and cleanings are carried out as recommended, the problem with diatoms should no longer exist and pond owners can once again enjoy their garden pond.

Facts worth knowing about diatoms in brief

  • Diatoms are usually the first colonizers of a new aquarium. It does not matter whether it is a freshwater or saltwater aquarium.
  • Shortly after the new setup you will find diatoms. This is because there is often a high concentration of silicates in the water at this time.
  • You do not have to fight diatoms immediately. Rather, they usually disappear by themselves when the silicate is depleted.
  • Or at least their population can be kept within safe limits.
  • In a well maintained tank they will not cause any problems.

Diatoms are a rather undemanding algae species. They require little light. Conversely, this means that you only have to provide good light conditions and the diatoms will never become a plague. But this is wrong again: Basically, diatoms only have a chance in poor lighting because the aquatic plants have little or no growth. Consequently, they do not consume any nutrients, the diatoms receive an oversupply of nutrients and can multiply explosively. In addition, fish such as catfish and barbs are quite fond of eating diatoms, so their use is a natural way to combat them. Good helpers are for example:

  • Snails,
  • Blennids
  • and also the many microorganisms present.
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Since diatoms are plankton, plankton traps and small crayfish will also enjoy the diatoms. So it should be easy to protect your marine aquarium from overgrowth of diatoms.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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