How about Hood Canal? Long Beach? (that said, only partially tongue in cheek) Would they work? Growing old is inevitable; growing up is optional. -- John Ruhland <john@drruhland.com> wrote: Regarding dolomite or other alkalinizing buffers: Apparently, dolomite varies in lead and other heavy metal content. I did not learn if any dolomite sources are low enough in toxins to warrant their use, but I did learn from one study (http://ehp.niehs.nih.gov/docs/2000/108p309-313scelfo/abstract.html) that 2/3 of ALL calcium supplements have higher lead levels than allowable by federal standards, they just don't require testing, so they are on the market. I think oyster shells would be a better alternative to dolomite. Even they may be contaminated, depending where they come from. Another advantage is that it is a more renewable resource. The best alternative may be a powdered mineral supplement powder, or refined calcium carbonate powder and epsom salts, although that would lack the important trace minerals. Can anyone recommend a source of high quality oyster shells or seashells? John _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member