When a chemical metering system is designed for a hydraulically balanced reciprocating metering pump, there are several variables to consider in order to ensure proper system operation and sound pump hydraulics. Process fluid properties to consider are vapor pressure, specific gravity, and viscosity. Some other variables that contribute to reciprocating metering pump applications are system suction pressure at the inlet, system backpressure at the pump outlet, length and diameter of system piping, and freedom from air and foreign matter. When all variables are considered and basic hydraulic principles are followed, the installation and operation of a reciprocating metering pump will be successful. This technical brochure is designed to provide a brief description and some general guidelines for applications of hydraulically balanced reciprocating metering pumps.