What's the actual difference between the two? The construction and/or materials? Going by the display, your scale has a resolution of only 0.1 oz/2.8 g. Even if the filter medium is different between the two filters the difference in weight may not be more than a gram or two and the scale may not display a different weight. Also, what's the accuracy of your scale? Does it accurately measure an 0.1 oz difference? Have you calibrated the scale with an appropriate weight?