This mixer will provide more mixing intensity than can be handled in an IBC container, especially without a top cover.  The IBC container is short enough that two (2) pitched-blade impellers would be difficult to position effectively.  The upper impeller will contribute to splashing and foaming, especially in the detergent.  One (1) four-blade pitched-blade impeller will be more than adequate and should be placed about 0.3 meters from the bottom.  A single four-blade pitched-blade 0.6 meters in diameter is more than adequate to mix the contents.  Even at 50 rpm, the mixing will be vigorous for a small tank.  At 110 rpm, the mixing intensity will probably be more than can be handled in an open container.  A 2.5 kW motor is appropriate for the 0.6 meter diameter impeller.  Larger impellers, 0.75 meters in diameter will overload a 2.5 kW motor.