I’m often asked about well water and carbon dioxide reduction… here’s a simple solution
Carbon dioxide reduction (decarbonation) – The simplest method for removal of carbonic acid is to pass the water through a tank containing limestone chips. A neutralizing filter of this type affects the carbonic acid just as does the underground limestone formation. The limestone in the filter reacts with the carbonic acid to produce calcium bicarbonate. In the same way, lesser amounts of magnesium bicarbonate are formed.
Note: Not all forms of limestone are suitable for this purpose. Excessively soft material may break down to form a solid mass and block the filter. The best types are hard, strong granules which retain their physical structure, even as they are dissolved.
This is not the only method I would consider but further assessment would be required.