Methods and apparatuses for automatically switching different aspiration levels to an ocular probe are disclosed herein. The probe may be a phacoemulsification probe. A first aspiration level, supplied by a first pump, may be applied to the probe simultaneously with ultrasonic energy. A second aspiration level, supplied by a second pump, may be automatically switched from the first aspiration level. Control feed back of the pumps may be varied according to set thresholds.