all you are trying to do is raise alkalinity. adding baking soda will do this. adding more, will raise it more. adding less will raise it less. it's not going to stop like a ph buffer would. your calcium level will also change. those work hand in hand, as does magnesium.
if your problem is low alk
, then add some baking soda and recheck....add again...and then you know what it took to raise it to your optimum range.
everyone's bio load is different and you won't be adding the same amount as the next guy will. your tank may also use alk
more or less than another system, depending mostly on coral load.
2 and 3 part supplements are sold together, to solve this possible issue.
check out bulk reef supply. they have some interesting videos to explain the chemistry.