Some aquatic plants prefer to take up nutrients with their roots. For them, there are special substrate fertilisers that are placed in their root zones.
Special capsules containing fertiliser, fertiliser sticks or clay balls containing plant nutrients are used for doing so. Some of them are placed directly in the areas to be fertilised with the help of tools like Bottom Release by Aqua Design Amano (ADA) or the Flowgrow Injector.
Substrate fertilisers add macronutrients like nitrate, phosphate and potassium and micronutrients like iron, manganese, boron, zinc, copper and molybdenum.