Wal-Mart sells magnesium carbonate for around 6$. Couldn't this be sprinkled into ascorbic acid and water to make magnesium ascorbate? I have thought of doing the same with potassium carbonate and sodium and calcium. Are there any advantages to this? Surely some of the ascorbate we get naturally is in these forms. I'm wondering if the excessive gas you're experiencing is a result of the magnesium carbonate combining in your digestive tract with the ascorbic acid and releasing carbon dioxide. Perhaps if you combined them before hand?