A system may include multiple strain gauges and multiple position sensors positioned on multiple pressure pumps. The strain gauges may measure strain in chambers of the pressure pumps. The position sensors may measure positions of rotating members of the pressure pumps. One or more computing devices may be communicatively couplable to the strain gauges and the position sensors to determine an adjustment to a flow rate of fluid through at least one pump using a strain measurement and a position measurement for the at least one pump such that a timing of changes in composition of the fluid delivered to into a first manifold at an input for the pressure pumps matches the timing of the changes in composition of the fluid delivered from a second manifold at an output for the pressure pumps.