Different ion effect

I need to have the highest concentration of (bi)carbonate ions in a water solution.

Thus far, my only idea was to use Potassium Bicarbonate (safe and cheap) as it has the highest solubility but it is yet not enough.

I was thinking whether adding both Sodium AND Potassium Bicarbonate, to saturation, would increase the total amount of dissolved Carbonates. Another solution, which might be more promising is using a complementary salt to make use of the 'Different ion effect' and increase the solubility.

Would any of these options be useful for my purpose? Thanks alot for the help.

• In theory, but at such high concentrations theory goes out the window. I'll point out that the pK value of bicarbonate will change in such a concentrated salt solution too. // By adding $\ce{NaHCO3}$ to a saturated solution of $\ce{KHCO3}$ I'd expect a little to dissolve but not much. Easy enough to try. // Details on what you're investigating might allow us to suggestions about other approaches. – MaxW Nov 2 '15 at 4:27
• Dissolving $\ce{KHCO3}$ in hot water might give you an unstable supersaturated solution. In other words it might be stable just long enough to do some experiment. – MaxW Nov 2 '15 at 4:38
• I have no idea what would happen with mixtures of $\ce{K2CO3}$, $\ce{CO2}$ and $\ce{H2O}$ under very high $\ce{CO2}$ pressures. – MaxW Nov 2 '15 at 4:42
• The final use is to have the solution react with another solution quickly to generate gas. This means temperature is out of the question as it is a volume of solution you need to carry around. Any idea on terms/nomenclature on saturated experiments and Ks changes I can look up (chemistry is not my field)?? Thanks – Pedro Luis Nov 2 '15 at 10:47
• You can buy liquefied $\ce{CO2}$ in canisters. Pop that open and it all goes to gas. – MaxW Nov 2 '15 at 16:41