I've used Calcium Carbonate (CaCO3) on a few batches already to raise pH; few times to restart a stuck fermentation and another to preemptively keep one going. It seems to do the trick, but I have yet to taste test any of them to see if it leaves a chalky taste.
After reading hightest's FAQ about Potassium Carbonate (K2CO3), I started looking around for suppliers. It seems like wine shops carry only Potassium Bicarbonate (2KHCO3). There are other vendors that carry potassium carbonate (photography and chemistry suppliers), but not wine and homebrew shops.
Is potassium bicarbonate a fair substitution? Do the same benefits mentioned in hightest's FAQ apply? I am not sure about putting something from a photography equipment vendor in my mead.
I got a 60lb bucket of clover honey that seems particularly acidic, so I definitely feel the need to buffer somehow.