Fertilizing the aquarium

The supply of nutrients necessary for aquatic plants. It includes macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, manganese, boron and others).

Detailed explanation

Aquatic plants need the same nutrients as terrestrial plants. The difference is that in the aquarium all the nutrients must be dissolved in the water or present in the substrate.

The macronutrients are nitrogen (N), phosphorus (P) and potassium (K). In aquariums with fish, nitrogen and phosphorus often come from the metabolism of the fish (manure, food). Potassium, on the other hand, is almost always lacking and must be supplemented.

Micronutrients include iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu), molybdenum (Mo), and cobalt (Co). Iron is the most important: plants that turn yellow between the veins almost always have an iron deficiency. Liquid fertilisers such as Tropica Specialized, Seachem Flourish and ADA Green Brighty provide a complete mix of micro.

Tom Barr's EI (Estimative Index) method is a popular approach. Generous quantities of all nutrients are dosed so that none are ever the limiting factor. Weekly water changes on 50% reset accumulations. It's simple and works well for aquariums with lots of plants and CO2.

The PMDD (Poor Man's Dosing Drops) method is more measured. Solutions are prepared starting from pure chemical salts (potassium nitrate, monopotassium phosphate, magnesium sulphate, micro mix) and are dosed daily based on the tests.

Substrate fertilisation uses tablets or capsules (such as Osmocote or root tabs) inserted near the roots of plants that feed mainly from the bottom (Cryptocoryne, Echinodorus, Vallisneria).

Attention: In marine aquariums, fertilisation has a completely different meaning. We are talking about the dosage of calcium, KH and trace elements for corals, not NPK for plants.

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