The design of the Yamitsu Mega Extra Large Filter is perfect filter for goldfish and koi ponds. The unit can be part buried if required as long as the outlet is above the pond water level. The filter can take a range of flexi hoses with the supplied inlet hosetail. Water enters the Mega Filter via a spray bar which distributes the water over the 1st stage of foam filtration. Water passes through a total of 5 layers of foam media before passes through the flocor media and back into the pond via a twin outlet that also have built in overflows.