ZOOBEST Special Substrate is made from a mixture of natural loams and clays, which have been enriched with the most important nutrients and trace elements. The coarse grain size of the substrate not only creates optimal conditions for water circulation and thus oxygen supply of the aquarium floor, but also provides the plants with an ideal rooting basis due to its porous structure. The plants can thus absorb the gradually released nutrients, which they need for healthy growth, through their roots.