[poldusia]

I have a large supply of Magnesium Carbonate Hydroxide, but what I need is Magnesium Bicarbonate. At this moment I cannot source any new materials and I am running out of time on my project.

If I combined the Magnesium Carbonate Hydroxide with carbonated water would it result at least in part in Magnesium Bicarbonate?

[Hunter2]

I would get a CO2 bottle used for soda stream in Bars, etc.  and press the gas through the solution. Only carbonate water is to weak.