Water care plays a central role in any aquarium. After all, water is the environment in which all living organisms must thrive, including fish, shrimp, crayfish, snails, other invertebrates, aquatic plants and the beneficial microorganisms that break down organic waste. These microorganisms not only mineralise food residues and make nutrients available to plants, but also remove harmful substances such as nitrite and ammonia from the water. For this reason, a well-functioning filter is essential for maintaining good water quality. Beneficial bacteria are found throughout the aquarium on all submerged surfaces, but they occur in particularly high concentrations within the filter. This is because conditions there are ideal, offering a large surface area, a constant flow of oxygen-rich water and a steady supply of nutrients.

The Dennerle Corner Filter is a reliable choice for smaller aquariums, while the Scaper’s Flow Hangon Filter is well-suited to larger tanks.

How do beneficial bacteria enter the aquarium? Nitrifying bacteria originate from soil and can survive in water as long as sufficient oxygen is available. They are present in the air as part of dust particles. In theory, an aquarium could simply be left open, and colonisation would occur naturally over time. Alternatively, filter material from an established aquarium, along with plants or decorations, can be introduced into a new setup. However, these methods rely heavily on chance. There is no guarantee that the bacteria introduced will be well-suited to the specific conditions of the new aquarium. Each tank develops its own unique microbial balance, which may not transfer effectively.

A more reliable approach is to use a bacterial starter such as Aquarium Starter Rapid by Dennerle. This introduces a wide range of bacterial species, allowing a stable and well-adapted microbial community to establish. The included bacteria booster provides nutrients that support rapid colonisation, enabling the system to stabilise more quickly. In some cases, this can significantly reduce the time required before introducing livestock.

In established aquariums, it is advisable to replenish beneficial bacteria after filter cleaning, following medical treatments or when problems such as excessive organic waste or unstable water parameters occur, particularly if nitrite levels rise.

Even in mature aquariums, environmental conditions may change, making it beneficial to support the microbial balance. Organic BactoElixier by Dennerle is designed for this purpose. The ampoules help maintain healthy filter bacteria populations. BactoElixier FB7 provides a balanced mix of beneficial bacteria and supports the regeneration of biofilms. These biofilms are an important natural food source for shrimp, snails and certain fish species such as Loricariid catfish, supplying essential proteins.

How can potential problems be identified?

Regular monitoring of water parameters is essential. Significant deviations often indicate the need for action. Test strips such as the WaterTest 6in1 by Dennerle allow quick measurement of key parameters, including pH, carbonate hardness, total hardness, nitrate, nitrite and chlorine.

If any values move outside the desired range, corrective measures can be taken promptly.

What if the carbonate hardness decreases?

A drop in carbonate hardness can occur due to bacterial processes in the filter or through the activity of snails, which require calcium for shell formation. A KH increasing product can help stabilise pH and provide essential minerals, particularly for snails. This allows carbonate hardness to be adjusted according to the needs of the aquarium inhabitants.

Clear Water Elixir by Dennerle helps to bind suspended particles and eliminate unpleasant odours. It is particularly useful for aquascaping, where crystal clear water is highly valued. The contained zeolite particles attract impurities and initially cause temporary cloudiness before settling in the filter. The result is clear, bright water.

Remember: Tap water is not the same as aquarium water

Tap water is treated to make it safe for human consumption, but this process can remove substances that are beneficial for aquarium life while adding others that may be harmful, such as chlorine or polyphosphates.

When using tap water for water changes, it should therefore be treated with a conditioner such as Aqua Elixir by Dennerle. This neutralises harmful substances such as chlorine and heavy metals like copper. At the same time, beneficial components removed during treatment can be reintroduced. Protective colloids support the health of gills, skin and mucous membranes, helping to shield fish from stress caused by aggressive water conditions.

Vital Elixir by Dennerle also supplies vitamins and trace elements that may be lacking or imbalanced in tap water. This helps to prevent deficiency-related health issues in both animals and plants.

For invertebrates, particularly shrimp, Nano Crusta Mineral by Dennerle provides a tailored blend of minerals and trace elements to support overall health and shell development.

Enjoy your aquarium!