Can I dose just alk in a 2-part?

[JosephM]

IMO, it will make no difference whether you use the alk part of B-ionic or baking soda for an initial alk boost, but I expect longer term you will need both parts. Unless nitrate is raising continuously, or water changes are messing with the alk somehow (or a couple of other unlikely things like the use of a sulfur denitrator), alk does not keep dropping without a proportional amount of calcium being used:

Here's a calculator that has more entries than most others:

Reef Chemistry Calculator

Yeah I have noticed that my calc and mag are starting to drop so I will continue baking soda and purchase a 2-part soon for when those levels get to where id like them.