An impeller, a system for mixing a fluid, and a method of mixing a fluid in a tank are disclosed. For a sufficiently small impeller diameter and maximum blade tip velocity, the disclosed impeller, system, and method are capable of accelerating a near-zero intake velocity fluid, to generate a mixing zone that is collimated enough to have sufficient velocity vectors to suspend particles at a large distance away from the impeller, while minimizing the required power draw. An impeller may include a hub defining a longitudinal axis and plural blades spaced circumferentially about the hub. Each blade may include a root portion and a tip portion. Each blade may define a leading edge having an approximately circular raked helical geometry. A system for mixing a fluid may include a tank for containing the fluid, a drive shaft for extending into the tank, and the impeller.