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Types of systems

Semi-closed system


The Aquarium Pula maintains optimal conditions by taking advantage of its location by the sea to pump fresh seawater, which flows through collecting pools to the aquarium tanks. The deep sea water is exceptionally clean and at ideal temperatures (15 - 17 °C). Before the seawater is used, the concentration of dissolved oxygen and pH levels are checked and balanced.

Closed system

Tropical pools require higher temperatures, thus minimal fresh water is added, and filtration systems are used to maintain microbiological and chemical parameters. The breakdown of food produces harmful compounds such as phosphates, and the metabolic by-products of fish contain high concentrations of ammonia, nitrite and nitrate. Physical (sand filters, protein skimmers, UV filters) and biological (biological filters) water purification methods are used to remove such harmful compounds.