ZooBest Special Auqa-Ground is a pottery clay, baked to a special formular, produced a highly porous substance, whitch is the main ingredient of this product. ZooBest Special Aqua-Ground has a neutral pH value, allows maximum circulation of water and air and therefor it is indispensable for aquarium and garden ponds. It is highly recommended for the following usages: A base covering for aquarium and garden ponds/-filtring granulat for fast and biological filters/ as a plant base for aquarium, pond, biotope and potted plants.ZooBest Special Aqua-Ground:3.0 litres bag5.0 litres bag10.0 litres bag20.0 kg big-bag