Perfect hold for plant roots: substrate with 0.2 - 0.6 mm grain size for freshwater and marine aquariums and terrariums Vigorous plant growth: prevents the seeping in of sludge and other waste material with its fine granulation and density Ideal for fish, invertebrates and plants: no release of unwanted pollutants into the water. Fine, round-shaped granite sand is gentle on sensitive barbels of bottom-dwellers. No light reflections – full colouring of plants and fish: easily scared animals feel more comfortable and show their full, natural colouring Contents: 1 bag Sansibar Dark. Not really suitable for undergravel heating cables Please note that the product is rather unsuitable for underfloor heating cables due to the fine grain.