A multistage pump includes a pump casing, a shaft, a first impeller, a second impeller, and a pipe. The shaft is rotatably disposed within the pump casing and has a longitudinal axis. The first impeller is disposed within the casing at a first position along the shaft. The second impeller is disposed within the casing at a second position and along the shaft. The pipe is detachably attached to the pump casing, and has an inlet and an outlet, the inlet disposed at the discharge of the first impeller and the outlet disposed at an eye of the second impeller, such that discharge from the first impeller can be conveyed to the eye of the second impeller.