0.2 - 1.7mm Grade 100% Natural and contains no artificial colours / dyes. Suitable for all Tropical, and Coldwater fish. NOT SUITABLE FOR MARINE AQUARIUMS Ideal for catfish, Eels, and Cichlids, etc which like to dig into aquarium substrate. Fantastic if used in planted tanks as the size of the grains allows plant roots to develope. This sand has been sifted and prewashed, enabling it to be used without cleaning, however some small dust particles may remain, but these will soon be cleared by your aquarium filter. Use 5kg per square foot of aquarium base. Packed in the United Kingdom.