A liquid ejection apparatus comprising a fluid line configured to extend into a tank and to receive a liquid, a rotary head being arranged on the pipe and fitted with a rotary hub that comprises a liquid ejection nozzle for ejecting the liquid, the rotary head being rotatable in a first direction and the rotary hub being rotatable in a second direction, such that the liquid ejected by the nozzle is ejected in a pattern on an interior surface of the tank. The liquid ejection nozzle comprises a first liquid outlet capable of ejecting the liquid in a first direction towards the interior surface of the tank, and a second liquid outlet capable of ejecting the liquid in a second direction towards the interior surface of the tank.