Abstract: The invention relates to a tank cleaning device comprising a tank cleaner (1) having a drive means (18) comprising a drive means component, a nozzle holder (5) rotatable about two axes (D, L) and at least one nozzle (6) arranged on the nozzle holder (5). In order to adapt the tank cleaner quickly to a particular use thereof, it is proposed that at least one of the components drive means (18), drive means component, nozzle holder (5) and nozzle (6) be designed as a replaceable element, that the type of replaceable element be defined by said component, that the tank cleaner (1) include a replaceable element holder, and that a first group (27) comprising at least two replaceable elements of one type be provided. A method for operating a tank cleaning device and a method for cleaning a tank are also proposed.