Fiji Cube 48 Gallon Shallow External Overflow Rimless Nano TankEXT Shallow The external overflow tank is a popular tank choice in the reef keeping hobby in recent years because of its highly customizable options in its filtration setup and its opportunity in maximizing space for aquascaping. Fiji Cube launches a series of ultra clear low iron glass aquariums with Fiji Cubes low profile external overflow design. The attractiveness and uniqueness of the Fiji Cube external overflow glass aquarium tanks stand out