Penn-Plax Cascade 300 Aquarium Filter

Year 300 (CCC) was a leap year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantius and Valerius (or, less frequently, year 1053 Ab urbe condita). The denomination 300 for this year has been used since the early Middle Ages / Medieval period, when the Latin language term / abbreviation "Anno Domini" ("In the year of Our Lord") for the calendar era became the prevalent universal / worldwide method for naming and numbering years. First beginning in Europe at the end of the Roman Empire (after the split of the Western Roman Empire and Eastern Roman Empire (later Byzantine Empire) in the early Middle Ages / Medieval period.

Then the Christian-oriented dating system then spreading west across the Atlantic Ocean with the Western European explorers and religious faith to the continents of the Americas of the Western Hemisphere, then through the simultaneous movement of the various Christian churches, and Europeans along sea trading routes with the military / political / economic / social influences of Colonialism / Imperialism spread worldwide to Africa, Asia and Australia / Oceania.

An aquarium (pl.: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquatic reptiles, such as turtles, and aquatic plants. The term aquarium, coined by English naturalist Philip Henry Gosse, combines the Latin root aqua, meaning 'water', with the suffix -arium, meaning 'a place for relating to'.

The aquarium principle was fully developed in 1850 by the chemist Robert Warington, who explained that plants added to water in a container would give off enough oxygen to support animals, so long as the numbers of animals did not grow too large. The aquarium craze was launched in early Victorian England by Gosse, who created and stocked the first public aquarium at the London Zoo in 1853, and published the first manual, The Aquarium: An Unveiling of the Wonders of the Deep Sea in 1854. Small aquariums are kept in the home by hobbyists. There are large public aquariums in many cities. Public aquariums keep fish and other aquatic animals in large tanks. A large aquarium may have otters, dolphins, sharks, penguins, seals, and whales. Many aquarium tanks also have plants.

An aquarist owns fish or maintains an aquarium, typically constructed of glass or high-strength acrylic. Aquaria with flat walls are known as fish tanks or simply tanks, while those with rounded walls are known as fish bowls. Size can range from a small glass bowl, a few liters in volume, to immense public aquaria of thousands of liters. Specialized equipment maintains appropriate water quality and other characteristics suitable for the aquarium's residents.

Filtration is a physical process that separates solid matter and fluid from a mixture.

Filter, filtering, filters or filtration may also refer to:

Plax is the name of a manufacturing factory that was located in Stonington, Connecticut. It began operations in Stonington in 1957, and was later purchased by the Monsanto Chemical Company. It specialized in the manufacturing of plastic bottles. The General Manager was Benedict U. Feole, formerly of New Britain, Connecticut and Westerly, Rhode Island.