Brief summary of the blog articles and an outlook for practice

In addition to aesthetic aspects, healthy plant growth makes a significant contribution to the chemical stability of the aquarium water. Other aquatic inhabitants benefit from the physiological performance of aquatic plants. Frequently reported reduced susceptibility to disease in fish and shrimps is very probably related to healthy plant growth. In the frequent case of imbalances in the nutrition of aquatic plants, mineral fertilization is sometimes necessary. The permanent supply of minerals that occurs in running waters can hardly be provided in the aquarium. The supply of minerals should therefore be ensured by mineral fertilization.

Fertilizers should be applied regularly(preferably daily) in small doses to ensure a continuous supply, even for plants with weaker competition. Occasional fertilization with high doses will benefit highly competitive species excessively. Moderate circulation of the aquarium water enables an even distribution of the minerals in the aquarium. Numerous proven aquarium products (e.g. fertilizers from DRAK-Aquaristik Dr. Andreas Kremser) are available for potassium and trace element fertilization. The author uses potassium nitrate (_KNO3) and potassium hydrogen phosphate (_KH2PO4) to adjust the Redfield ratio.

Another important characteristic of running waters is the permanent removal of mulm and toxins. As many fish react sensitively to increased concentrations of microorganisms (e.g. Loricariidae, Callichthyidae), regular water changes should be considered a matter of course for reasons of animal welfare. In addition to removing mulm and toxins, targeted water changes can also influence the mineral concentrations (e.g. N/P).

The pH of the aquarium water has a significant influence on the availability and uptake of minerals by aquatic plants. It can be kept in a favorable range by adjusting the carbonate hardness and an additional_{CO2 supply}. An additional _{CO2 supply} enables more efficient utilization of other minerals dissolved in the water. To avoid unnecessarily expelling _CO2 produced by the respiration of plants and animals, filter outlets should be installed below the water surface and _O2 diffusers and diffusers should only be operated at night.

The lighting of an aquarium controls the mineral requirements of aquatic plants and can indirectly have a lasting effect on the pH of the aquarium water. Strong lighting always means that aquatic plants require more minerals. In the case of carbon, this increased demand can lead to instability in the acid balance of the aquarium water (biogenic decalcification). Although there are aquatic plant species that require a lot of light, the moderate lighting levels of an average aquarium are sufficient for most common species.

The author has had positive experiences with substrate filters in recent years. These were installed upstream of external filters so that the filter surface area was greatly increased. The flow through the substrate allows plants to absorb minerals from the substrate water flow, minimizes rotting and stabilizes the temperature of the substrate. The use of substrate filters makes it possible to create a more natural substrate. A mixture of sand (Ø 0.3 - 2.0 mm, 75 %) with aquarium clay (1.0 - 4.0 µm, 25 %) can ensure that the substrate is flooded by regularly removing mulm.

Ensuring healthy plant growth through regular water changes and mineral fertilization in combination with structural measures has many advantages and enables animal-friendly and cost-effective aquariums in the long term.