Abstract: Pumping systems and methods for delivering a plurality of different pumpable materials serially at a location at substantially the same flow rate includes a plurality of diaphragm pumps, wherein each diaphragm pump has a first chamber for receiving a hydraulic fluid from a first and/or second hydraulic fluid source and a second chamber for receiving a material to be pumped from one of a plurality of pumpable material sources. A sensor is provided for detecting the pressure of the hydraulic fluid in each of the first chambers of the plurality of diaphragm pumps and is operable to activate the source of hydraulic fluid to ensure that the hydraulic fluid in each of the first chambers of the plurality of diaphragm pumps has an equivalent pressure.