Abstract: A fluid vacuum pump includes a motor assembly including a single motor or multiple motors, where one motor may be configured for operation in a first medium and another motor may be configured for operation in a second medium; an impeller assembly including a single impeller, which may of a fixed or variable configuration, or multiple impellers, where one impeller may be configured for operation in a first medium and another impeller may be configured for operation in a second medium; and a linkage operatively connecting and adjustably transmitting power from the motor assembly to the impeller depending on the type of medium present.