Dennis S. Gray's post states he has "10 - 20 ppm nitrates" in his tap water. ????? EPA maximum allowable nitrates in tap water is UNDER 10 ppm. If your tap water is from a Public Water System, I think perhaps (1) your Nitrate test is a bit less than accurate, or (2) The EPA would be VERY interested in talking with the operator of your water utility! ( :-) )