Abstract: A mixer assembly having vertically displaced differential agitators. The first agitator is a primary mixing component formed of a hub having slots for positioning and securing radially extending angularly displaced stirring members. The hub is of a unitary construction and has three arcuate generally convex sidewalls attached about a central bore for receiving a drive shaft. The spaces between vertically extending edges of the sidewalls form the slots into which the stirring members are pivotally attached. The second agitator is a secondary mixing component formed of a disc shaped retaining member with stirring members angularly displaced about the edge of the disc. The stirring members of both the first and second agitators extend horizontally with rotation of the drive shaft, with the first agitator effective for both loosening sediment and stirring, while the second agitator increases the stirring effect.