i am using both an elos and a salifert kit right now. the elos is quicker, fewer steps. the salifert more precise, more steps. i.e. with the elos its either 1100, 1200, 1300,1400 ppm...with the salifert the increments are smaller, 1130, 1160, 1190, 1220, 1250 ppm etc...