Dolomite as a buffer

[dgh5]

Hi,
I was wondering if dolomite acts as a buffer in the same way that aragonite does. If so, can anyone tell me what pH it buffers to. I think i remember hearing that aragonite buffers to 8.3, can anyone tell me a similar number for dolomite? Is it suitable for reef use?

[Randy Holmes-Farley]

Neither is a useful buffer for reef aquaria. Aragonite does not dissolve unless the pH drops well into the 7's.