The basics of these tanks absolutely circumduct about the admeasurement of the catchbasin itself. While accustomed beach tanks aim to yield a baby area of the sea and accept it reside in an aquarium, the nano catchbasin takes that to addition level, aggravating to do so in a abate tank. While some say that annihilation abate than 40 gallons is a nano tank, there are others who anticipate that the catchbasin have to be beneath than 20 gallons.