ReeFlowers Caledonia Sea Water is treated sea water free of organisms that could cause problems in aquariums. It does not contain any additives and has been enriched with highly purified minerals to achieve the closest possible match to natural ocean water in terms of salinity kH calcium magnesium potassium and strontium levels as well as trace elements that help ensure that living organisms stay healthy for a long time. It has been treated to remove elements such as phosphate nitrate iron and silicate which may promote moss growth. Caledonia Sea Water is similar to natural ocean water in terms of content. You may add Caledonia Sea Water to existing aquarium water in new installations to help establish natural habitat functions more quickly or you may use Caledonia Sea Water in the tank exclusively. It can also be used for water changes.