An impeller seat for a pump, the impeller seat comprising an inlet wall, an inlet radius, and a guide pin connected to and extending radially inwards from the inlet wall. The guide pin includes a tip radius. A 40%-circle is offset radially inwards from a circular intersection forty percent of the difference between the inlet radius and the tip radius. The guide pin comprises a leading edge configured for scraping off pollutants from an impeller of the pump, and, at least between the inlet wall and the 40%-circle, comprises a pre-leading edge located upstream the leading edge of the guide pin, seen in the direction of rotation of the pump and seen in an axial direction.