Is that a spider that caught a fungus gnat ?
Gypsum is the choice if you don't want to effect the pH.
As an exact science it might be. In gardening circles it's thought to be neutral. I have not seen calculations that use it's acidic properties so I'm guessing it's very mildly acidic. It will be difficult to calculate the dolomite to offset it, without any actual numbers.
A page of search results regarding it's use to lower pH, all say it's it's neutral. I'm at a loss with that one.