Would alkalinity and CA stay constant in a tank if nothing else was added?

[vessxpress1]

Thread title is pretty self explanatory. I'm doing an experiment with my tank and just wondering. If you had a new empty tank with saltwater would they remain the same for an extended period of time? If not would they drop and by how much? I'm testing my alk and CA usage since last Thursday. I have quite a few frags and coraline starting to take off. I'm not in a danger zone yet but rapidly approaching the safety zone. I'm losing about 1 dkh a day or so and CA has dropped 40 ppm since 4 days ago. Just wondering if it is 100% from coraline and coral uptake.

 

[Doctorgori]

BRS. has a salt storage vid; they tested different salt brands.... the vid won’t be hard to find

 

[Randy Holmes-Farley]

Thread title is pretty self explanatory. I'm doing an experiment with my tank and just wondering. If you had a new empty tank with saltwater would they remain the same for an extended period of time? If not would they drop and by how much? I'm testing my alk and CA usage since last Thursday. I have quite a few frags and coraline starting to take off. I'm not in a danger zone yet but rapidly approaching the safety zone. I'm losing about 1 dkh a day or so and CA has dropped 40 ppm since 4 days ago. Just wondering if it is 100% from coraline and coral uptake.

The high alk and low organics in salt mixes makes it especially prone to calcium carbonate precipitation. Red Sea shows this precipitation in videos.

But if you have rock and corals there, it is not the scenario you are actually asking about.