Magnesium for GERD and for Crohn's

The last month or so I've been having GERD. I've been on Dexilant for 4 months and it has controlled the GERD. I'm wondering if it has stopped working. I do watch what I eat. I have Crohn's and PSC. If I take Maalox it relieves my GERD very quickly. One of the ingredients in Maalox is Magnesium. I've been researching Magnesium and there is much info on taking a supplement (not more than 350 mg per day) to help with GERD. Also indicated people with Crohn's can be deficient in Magnesium. I don't know if I've ever been tested. Wondering if anyone is taking a Magnesium supplement?