A study of the scale inhibition in water solutions induced by a galvanic device known as the "allotropic cell" is presented. The scale inhibition effect is related to the release of metal ion impurities of Zn+2 and Cu+2 from the surface of the device. An induced crystal structure modification of the precipitates with a trend to form the metastable aragonite structure is produced. The antiscale effect results from changes in crystallization behavior promoting bulk solution precipitation rather than formation of adherent scale.