Fluval Stratum is a volcanic soil collected from the mineral-rich foothills of the famously active Mount Aso volcano in Japan, the biggest in the country and one of the largest in the world. It is an ideal substrate for stimulating the growth of a wide variety of stunning aquatic plants in freshwater aquariums. Delicate root systems are able to easily penetrate and spread throughout this substrate, allowing plants to obtain a host of readily available beneficial nutrients to aid in their growth. The substrate is rather light and non-compacting, helping to support beneficial nitrifying bacteria within the tank. They quickly colonize its porous structure, helping to maintain a healthy, optimal water quality for plants and other inhabitants. Fluval Stratum helps maintain a neutral to slightly acidic pH that is ideal for most plant species, as well as for the fish and shrimp (such as cherry, ghost and amano) typically kept in planted aquaria. As an added bonus, the substrate provides a refuge for newborn shrimp, allowing them to avoid early-stage predation and to remain hidden until they are large enough to move freely without fear. Fluval Stratum will not discolor your aquarium water, and even helps to control organic discoloration often caused by the use of natural driftwood.