>A negative reading obviously means you are in > the presence of de-ionizing radiation. Is that how they make de-ionized water? ;-> Colette Tremblay Recherches en sciences de la vie et de la santé Pavillon Charles-Eugène-Marchand Université Laval Québec QC Canada G1K 7P4 Tél: (418)656-2893 Fax: (418) 656-7176 Internet: coltremb@rsvs.ulaval.ca