The pathogenesis of ectopic gastric mucosa is a matter of debate between a congenital-embryological-and an acquired origin-consecutive to a gastroesophageal reflux (GER) like Barrett's esophagus -, the most commonly accepted theory being that these areas are embryological remnants.
Standard size latex filled helium balloons stay afloat for approx 8 - 12 hours, metallic helium filled balloons float for 2-5 days. I have found that a 36 latex helium filled balloon can stay afloat for a number of days due to the thickness of the balloon and the massive quantity of helium.
Balloon Time Helium Tank: 1  Portable. 2  Latex Balloons: Tank will fill approximately (50) - 9 inch latex balloons or (27) - 11 inch latex balloons.  Mylar Balloons: Tank will fill approximately (27) - 18 inch mylar balloons or (20) - 20 inch mylar balloons.