Some of the polysaccharides can help coat the tissues to soothe them, but it is not going to get rid of the problem, which stems from a lack of stomach acid to begin with. This leads to fermentation in the stomach and resultant gas production. As this gas escapes up the esophagus it carries traces of acid with it leading to the GERD. If you want to treat GERD you need to increase your stomach acid. You can use apple cider vinegar, or betaine HCl as substitutes. To help get your own production of stomach acid back up I recommend zinc 50mg daily with a large meal, B vitamins, and trimethylglycine (TMG) 500mg 3 times daily.
You should avoid antacids, acid blockers and alkalinizers like alkaline waters. These wipe out the remaining stomach acid and interfere with the absorption of nutrients required to form stomach acid.