One of the literaly heaviest components in aquaristics is the substrate. So, let's see: Is a riverbed or the seafloor made of glass? We guess no! As a rule the most under water floors, bee it a river or the sea are mostly made of sand, gravel and a mixture of rock and sludge. Modern soils try to recreate a natural environment and are much more capable than just looking good. A sensible combination of components enables for optimal flooding of the bottom, which leads to a healthy microfauna as well as healthy aquarium plants and fish. The Fluval substrates in our aquaristics online shop fulfil several tasks in the aquarium. On the one hand, the plants can take root in the substrate, and on the other hand, the soil, which consists of baked Japanese clay, can provide nutrients and minerals, as well as regulate the pH - value of the aquarium water and buffer it for more sensitive aquarium inhabitants. Another advantage is that useful bacteria settle optimally on the surface and contribute to nitrification and the breakdown of pollutants.