Can an air pump be too strong for guppies?

If an air pump is simply being used to provide bubbles/circulation then you can put a G clamp on the airline and reduce the airflow if the fish seem to be having a hard time. Need more information to fully answer this question. A 10 gallon tank with an outside power filter sized correctly for the tank is not a problem even for baby guppies. If the concern is with the intake tube, place a mesh cloth or section of an old pair of hosiery around the end of the tube.