Unless your pH is already at 8.4 (the pH of baking soda), this will probably raise your pH depending on the amount of acidic buffers in your water.Ways to increase kH
Adding sodium bicarbonate (baking soda). One teaspoon of baking soda added to 50 liters of water can raise the kH of the water by approx 4 deg dH without a major affect on pH.
No, carbonic is such a weak acid that it doesn't have any appreciable effect on kH.Ways to lower kH
Injecting carbon dioxide (CO2)
Since those calculators don't work unless carbonates are the only buffer in the water it is doubtful that he has a CO2 concentration anywhere near 60ppm.Using the KH-PH CO2 calculators your CO2 concentration would be 60.4ppm.