Tunze Doc Skimmer 9012 Genuine UK part covered by UK Warranty The comline doc skimmer 9012 is designed for use in mixed reedf aquariums with 200 to 1,200 litres (53 to 317 us gal), soft coral aquariums upto 1200 litres (317 us gal), or for sensitive reef biotapes with hard corals with up to 500 litres (132 us gal). it operates according to the tunze flash skimming principle and acquires the water through an effective 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 o.