A system may include a main line for delivering a first gas, and a sensor for measuring a concentration of a precursor in the first gas delivered through the main line. The system may further include first and second sublines for providing fluid access to first and second processing chambers, respectively. The first subline may include a first flow controller for controlling the first gas flowed through the first subline. The second subline may include a second flow controller for controlling the first gas flowed through the second subline. A delivery controller may be configured to control the first and second flow controllers based on the measured concentration of the precursor to deliver a first mixture of the first gas and a second gas and a second mixture of the first and second gases into the first and second semiconductor processing chambers, respectively.