organic dolomitic limestone works great. make shelves out of
limestone works great. it has both calcium and magnesium.
DONT USE PLASTER OF PARIS, oyster shells.
Ingrid

On Wed, 1 Aug 2007 08:17:34 CST, DavidM
wrote:
Would acid in the water act on chalk in the same way? Could a lump of
chalk be used as a slow release aid to buffering?