GERD is the resuly of a weak lower esophageal sphincter rather than food intolerance.
A number of foods can stimuate excess acid.
Whereas most fruits are acidic, they actually reduce the acidity of the stomach - except for citrus fruits.
Although we are all different and respond to different foods in different ways, citric acid is one of those compounds that are most likely to produce excess acid. It won't cause reflux but the reflux will be more noticeable because of the strength of the acid.
Excess acid should be combatted with a PPI (eg omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, dexlansoprazole). It may take a few days before you start noticing the difference.
If you experience acid reflux frequently, you need to have it checked by a doctor who may call for an endoscopy. It can cause Barrett's Rsophagus which is potentially pre-cancerous.
GERD is the result of a weak lower esophageal sphincter rather than food intolerance.