A micro-abrasive blasting device and method for perturbation control using a plurality of delivery conduits of various lengths and/or apertures. The user is able to individually open and close bypass conduit pinch valve(s) external to micro-abrasive blasting device to affect the perturbation intensity internal to the mixing chamber. By selectively opening and closing flow through delivery conduits it is possible to provide a more consistent perturbation rate and select the perturbation intensity internal to mixing chamber.