Filter may refer to:
Aquarium filters are critical components of both freshwater and marine aquaria.Aquarium filters remove physical and soluble chemical waste products from aquaria, simplifying maintenance. Furthermore, aquarium filters are necessary to support life as aquaria are relatively small, closed volumes of water compared to the natural environment of most fish.
Animals, typically fish, kept in fish tanks produce waste from excrement and respiration. Another source of waste is uneaten food or plants and fish which have died. These waste products collect in the tanks and contaminate the water. As the degree of contamination rises, the risk to the health of the aquaria increases and removal of the contamination becomes critical. Filtration is a common method used for maintenance of healthy aquaria.
Proper management of the nitrogen cycle is a vital element of a successful aquarium. Excretia and other decomposing organic matter produce ammonia which is highly toxic to fish. Bacterial processes oxidize this ammonia into the slightly less toxic nitrites, and these are in turn oxidized to form the much less toxic nitrates. In the natural environment these nitrates are subsequently taken up by plants as fertilizer and this does indeed happen to some extent in an aquarium planted with real plants.
Filter Theatre is a British theatre company known for its groundbreaking use of sound. The company makes new work and also reinterprets classic texts, such as Three Sisters (2010, Lyric Hammersmith).
Svetlogorsk (Russian: Светлого́рск ), prior to 1946 known by its German name German:
Rauschen (Polish: Ruszowice; Lithuanian: Raušiai), is a coastal resort town and the administrative center of Svetlogorsky District of Kaliningrad Oblast, Russia, located on the coast of the Baltic Sea on the Sambia Peninsula, 39 kilometers (24 mi) northwest of Kaliningrad, the administrative center of the oblast. Population: 10,772 (2010 Census); 10,950 (2002 Census); 11,881 (1989 Census).
Svetlogorsk is situated in the historical region of Sambia of East Prussia. It was established in 1258 as a Sambian fishermen settlement named Ruse-moter (lit. region of cellars). The Teutonic Order that conquered the land gradually corrupted the name into Rause-moter, Raushe-moter, and finally Rauschen.
In the early 19th century, the place became fashionable among German vacationers. On June 24, 1820, it was officially recognized as a spa town. During his visit to Rauschen in 1840, King Frederick William IV of Prussia ordered the sea embankment to be beautified. The arrival of the Königsberg railway in 1900 boosted the resort's popularity. A cable railway and a racecourse were constructed in Rauschen before World War I. Otto Nicolai and Thomas Mann were among the celebrities who stayed there.