Unless your fish are hanging at the top of the water gasping you dont need
an airstone.

"FBCS" wrote in message
...
I have read lots have natural ponds/VG filter no falls and they do not
talk
of the need for an air pump/stone. How necessary is a air pump/air stone
to
the health of the pond? Do you calculate size by gal with this type of
pump
also. If not what would be a typical size for a pond, better yet, what do
you use? Joann