1 kilogram of Red Sea Live Reef Sand Red Sea Live Reef Base Ocean White 0.25mm to 1mm grain size. 1kg of wet Live substrate packed in sealed fish bag for sending through post. 1kg = 1000grams A premium aragonite sand subsatrate for marine in reef aquariums from a natural Aragonite source. Live Reef Base from Red Sea is high in essential elements and promotes stability of pH and buffers alkalinity KH levels. Live Reef Base is easy to use and is ideal for all marine fish and corals. As this is a Live Substrate, it speeds up the cycle time and reduces the time from set up to adding livetock into your aquarium. This Live version of Reef Base contains millions of beneficial bacteria , which speeds up the maturation process and allows quicker introduction of corals. The bacteria is gelled onto the grains and packed sterilized in natural seawater. Red Sea Reef Base is an oolitic aragonite substrate, formed through natural precipitation and collected from a renewable source meaning using Reef Base will not have a detrimental effect on the environment unlike some other Marine sands available. This premium substrate helps maintain an ideal pH of between 8.2 and 8.3 and is prepared by exposing the sand to UV light, screened and even mechanically washed, then washed again resulting in a cleaner substrate.