The Zwietering correlation for the just-suspended speed has been modified to include baffling and geometric effects (impeller-to-tank diameter ratio and impeller off-bottom clearance) for two impeller types (high-efficiency and pitched-blade). Baffles are generally not required when using square tanks although they improve solids suspension performance of pitched-blade turbines. Comparison of square tank solids suspension to that in a fully baffled cylindrical tank has also been made. Very little difference was observed in the power number, but the just-suspended speed, torque, and power requirements were higher in the square tank.