Electrolytes are essential for the uptake of oxygen and the release of carbon dioxide and ammonia through the gills. A lack of electrolytes may cause serious health problems. API® AQUARIUM SALT, made from evaporated sea water, provides these essential electrolytes. AQUARIUM SALT does not evaporate, and is not filtered out, so it should only be added with each water change. Care should be taken when using salt with live plants, as some plants may be sensitive.