Ascorbates are not acidic! That is salts of ascorbic acid such as can be made from Magnesium carbonate and ascorbic acid to produce magnesium ascorbate.

Or sodium bicarbonate with ascorbic acid to produce sodium ascorbate but that is not as beneficial as magnesium ascorbate. You get both important magnesium and vitamin C with magnesium ascorbate.

It's easier on the stomach too.