Detergent applications may require different levels of mixing intensity depending on how the process is done.  The following two options will provide moderately intense mixing or adequate mixing depending on the processing requirements.  Both options, as described, use the same impeller system.

For moderately intense mixing:  a 2.2 kW motor, with a shaft speed of 68 rpm, and two (2) four-blade, 45-deg, pitched-blade impellers, 0.75 m in diameter with 0.15 m wide blades.

For adequate, but less intense mixing:  a 1.1 kW motor, with a shaft speed of 56 rpm, and two (2) four-blade, 45-deg, pitched-blade impellers, 0.75 m in diameter with 0.15 m wide blades.
 
Both designs assume that the mixer will be center mounted in the tank and that the tank will have baffles, four (4) baffles at 90 deg, 0.125 m wide to avoid uncontrolled swirling.  Without baffles, the moderately intense mixing selection would probably splash out of the tank.