the Dolomite Lime I use is called "prilled" .. it's little pellets, probably what he is talking about ... and, that brings up MY question ... I've been using it for awhile, and it works great for bringing up my pH in my acid water, plus adds calcium and magnesium ... but, although it dissolves rapidly, it does leave a dark, fine-sand, a gritty residue in the jug ... almost black, l have assumed it is the magnesium ... any clue on that ??