Before you bring your alk up, check your calcium.
(hopefully) simple explanation:
If alkalinity is low and calcium is high, add 1tbsp baking SODA to one quart of freshwater, stir hard or shake vigorously and pour in very slowly. It should raise alk by 1dKh. Adjust as needed, and test after every dose.
If alkalinity is low and calcium is low, add 2tbsp kalkwasser to 1g freshwater, stir/shake, wait two hours minimum to let impurities settle at the bottom then drip using an airline tube and gang valve in overnight at a rate of 3-4 drips per second. Test after every dose until you get the hang of it.
Your calcium has to be at the same levels as your alkalinity or else you didn't do anything. If you suddenly bring your alkalinity up, your calcium may dip way down. You'll need to check it either way.