The answer to the question is that the impeller size and rotational speed are incompatible with the vessel size, regardless of the contents. Any 3-ft diameter impeller operating at 300 rpm will send the tank contents flying. The least power input would be with a hydrofoil impeller, but at 40 hp, the contents would remain in the tank for only seconds, unless the vessel were completely enclosed. A pitched-blade turbine would require a 250-hp motor and a straight-blade impeller would require a 500-hp motor. Even at 50 rpm, a straight-blade turbine would provide intense mixing, with a 3-hp motor. Either the impeller size or the rotational speed must be drastically reduced to make this design feasible.