Match the insulin to your exercise, remember that it takes about three hours or more for a change in basal to take effect on the pump.
Generally aerobic exercise needs a reduction, and may also need carbs to support it, anaerobic may increase BG and may need an increase in basal, or a small bolus.
You'll need to experiment to find your own requirements, but remember to test before exercise, every 30-45 mins and afterwards.