First things first. Read this:
Chemistry and the Aquarium
After reading this, your head is probably spinning in circles. Randy Holmes Farley has a way of making that happen. Look, i'm no chemist. Heck, I hate chemistry so much that I substituted a 400 level Physics course for a 101 Chem Lab when I was in college.
That being said, the basic answer to your question, for the purpose of marine aquarium care, is YES. We are really only concerned with carbonate and bicarbonate buffers, as they relate to calcium. Therefore, a Carbonate Hardness test kit should, in theory, give you what you need.
However, if you really want to be on board with what most of us here are doing, order an alkalinity test kit online. You can find it here:
Alkalinity Pro Test Lab | Alkalinity Test Kits & Refills | Test Kits & Refills | Aquarium - ThatPetPlace.com
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