27.06.2016 Prepare saltwater properly Saltwater is the basis of a marine aquarium. Photo: © sera Saltwater is the basis of a marine aquarium. But how is this actually prepared correctly? Saltwater for aquarium purposes is prepared with artificial sea salt, as the maritime aquarium inhabitants require stable conditions without strong variations. It is best to use purified water for preparing marine water. Tap water usually contains numerous additives and natural substances that may harm the living beings in the aquarium. Therefore it by all means needs to be deionized or filtered by an R/O system in advance. Aquarists need a sufficiently large container for preparing marine water – for instance, a rainbarrel of corrosion-proof plastic material is perfectly suited. The pollutant free water is first filled in, by and by followed by the artificial sea salt such as marin salt or marin reef salt by sera. It can be used when all salt has dissolved and a salinity of 35 permille, i.e. 35 grams per liter (4.725 oz./US gal) is achieved. However, factors such as nitrate level and density should be checked with special water test kits or a hydrometer, for instance by sera. Levels below 10 mg/l (ppm) nitrate and a density of 1.023 are optimal. Tip: The marine water should be well agitated and aerated by a pump in the container for approximately 24 hours. The water then will appear entirely clear.