The large Comline® DOC Skimmer 9012 is designed for use in mixed seawater aquariums / soft coral aquariums from 200 to 1,200 liters (53 to 317 USgal.), or for sensitive reef biotopes with hard corals up to 500 liters (132 USgal.). It operates according to the Tunze® flash skimming principle and acquires the water through an efficient surface suction with a surface film removal, and can therefore also be used as a "stand-alone" solution in the aquarium. The TUNZE® Foamer generates large volumes of fine air bubbles with a diameter between .1 and .3 mm (.004 - .012 in.) and is especially quiet during the operation.