Abstract: Systems and methods are disclosed to mix a base ingredient, such as water, with an additive, such as a cleaning concentrate. A dispensing system of the disclosure can include a container filling apparatus. The container filling apparatus can include one or more source containers that contain an additive to be mixed with water or other base ingredient. The container filling apparatus can include a vacuum manifold and a Venturi body assembly (VBA). The additive can be flowed through the vacuum manifold and into the VBA. In the VBA, the additive can be mixed with water or other base ingredient, and output to a receiving container. As the additive is flowed through the vacuum manifold, vacuum pressure in the pressure manifold can be measured by a pressure sensor. A controller can input pressure data from the pressure sensor over the course of a dispense event. Over the course of a dispense event, flow of additive can be varied or modulated based on the pressure data.