Oliver Knott: Which fertilizer for my aquarium?
A recommendation for suitable fertilization

Especially in the field of planted tanks there is an unbelievable number of variants, depending on the aquarist’s aspirations, the technical equipment and, of course, the aquarium plants themselves. Oliver Knott gives some important hints regarding the nutrient supply for the plants in different aquarium types.

Low requirements

undemanding Anubias

In an aquarium with easy-to-keep aquatic plants, simple lighting and no CO2 injection system, Oliver Knott recommends a classic complete iron fertilizer, e. g. the Aqua Rebell Mikro Basic Eisen presented in the video. In addition to iron, this liquid fertilizer contains other important trace elements such as manganese, copper, zinc, as well as the macronutrient potassium. The nutrients are stabilized by complexing agents so they stay available in the water for a prolonged period. For this reason, a weekly fertilization is possible with this product.

Medium requirements

Hemianthus glomeratus

In planted tanks or aquascapes with moderate lighting and as additional CO2 supply system, Oliver Knott recommends supplementing nutrients with Aqua Rebell Mikro Basic Eisen and complement it with an NPK fertilizer (used here: Aqua Rebell Makro Basic NPK). This macronutrient fertilizer closes nutritional gaps and adds those elements that are needed by aquatic plants in larger amounts. It contains nitrogen, potassium, phosphate and magnesium.

High requirements

demanding stem plants

In so-called intense-light aquariums with many fast-growing plants or in aquariums with red stem plants, especially the macronutrient nitrogen may be used in such large amounts that even though nutrients are supplied with an NPK fertilizer, a shortage may arise. With intense lighting and a correspondingly ample CO2 fertilization, the aquatic plants are encouraged to grow quickly. A pure nitrogen fertilizer such as the Aqua Rebell Advanced GH Boost N, presented by Oliver Knott in the video, may be the proper remedy. It is an excellent supplement for the two liquid fertilizers Aqua Rebell Mikro Basic Eisen and Aqua Rebell Makro Basic NPK.

If you want to learn a bit more about the nutrition of aquatic plants, we recommend our series of articles on Fertilizing a planted aquarium, part 1, part 2 and part 3 for reading.