Various aspects of the disclosure are directed to providing structures that define a radial gap between an impeller and a pump casing element that facilitates minimizing the movement of fluid into the radial gap in a manner that lessens the impact, and consequent degradation, of the inner surface of the pump casing element by movement of abrasive particulates out of the radial gap, which is accomplished by providing a suction inlet arrangement of an impeller and pump casing element that are angled from the eye of the impeller to the outer periphery of the impeller in a direction away from the back shroud or drive side of the impeller and toward a first end of the pump casing in which fluid is introduced into the pump casing.