A liquid ejection apparatus (100) for cleaning of a tank (40). The liquid ejection apparatus (100) comprising: a base member (105) having a first end (105a) for receiving the liquid (L) from a liquid line (101), a rotary head (106) that is rotatably connected to the base member (105) and a rotary nozzle hub (110) that is rotatably connected to the rotary head (106). The rotary nozzle hub (110) comprises a primary liquid ejection nozzle (112) for ejecting a liquid (L) in a pattern towards an interior surface (41) of the tank (40). The primary liquid ejection nozzle (112) has an outer, concave surface (112s) that faces the rotary head (106).