I have GERD, but how do I know if the symptoms are because of too much or too little acid in the stomache?

the simplest answer is often neither. The problem is because the acid that is in the stomach splashes or refluxes back up into the esophagus irritating tissue that isn't supposed to be exposed to acid. Medications to treat GERD are often 2 types. 1 causes increased tone of the muscle to better close off the esophagus from the stomach after swallowing and 2 decrease acid production so that less acid is available to reflux and cause symptoms. Source(s): er md

Take a tablespoon of vinegar and put it in 8 oz glass of water and drink it.If symptoms get worse you have an over production.If symptoms improve you have too little acid.Bit of advice "lay off the antacids "they only make the problem worse.they completely stop the production of acid and neutalizes what is already there and the food lays in your stomach and putrifies.
Its a very common problem presenting as heart burn, acid erucatation, sensation of stomach contents comming back in food pipe, specially after a large meal, aggravated by stooping or lying flat. Some cases have an anatomical defect (hiatus hernia) but majority r only functional (LES relaxation in d absence of swallowing). Repeated reflux of acid gastric contents into lower 1/3rd of esophagus causes esophaagigis, erosion, ulcers, strictures, and increases d risk of esophageal carcinoma.

Acidity of gastric contents is d most important aggressive factor in causing symptoms and esophageal lesiions.

Treatment:

REFLUX LIQUID: Sod. alginate 200 mg + alum. hydrox. gel 300 mg trisilicate 125 mg/10 ml susp.