Gary, do you or anyone else of the forum, know of any connection between using Calcite in water treatment and kidney stone formation?
I've never heard of it. All calcite (basically CaCo3; limestone) does is buffer acidity and increase the hardness of the water. IIRC, the main cause of kidney stones is an insufficient volume of water per day to flush the kidneys properly.
Many people believe that hard water is better to drink than softened or naturally soft water and I don't hear that they have kidney stone problems. So I don't think hard water has anything to do with kidney stones, just the daily intake of water of whatever kind.
Quality Water Associates