Pentek DBC-10EX2 10 inch x 4.5 inch Big Blue Whole House Filter

This is a review of the Pentek DBC-10EX2 granular activated carbon cartridge with KDF 55 Media. I''ve been using this cartridge for several weeks. This is a big cartridge intended for whole house applications, measuring 10" x 4.5". I chose this cartridge and the Pentek Big Blue 10" housing for my kitchen sink in order to not diminish the flow rate at the kitchen tap. Because this particular unit is so large, I installed it on the supply line in the basement, just below the kitchen floor as opposed to under the sink. I already have a whole house sediment filter as a pre-filter for this unit. My well water was already pretty good; however, a recent professional test showed my arsenic level is .012 parts per million (12 parts per billion), which slightly exceeds the EPA limit of .010 ppm (10 ppb). I was hoping this cartridge would completely remove the arsenic, but that has not been the case. It has, however, reduced the arsenic from 12 ppb to about 7 ppb. I did a follow-up test of both my filtered and unfiltered water using a home test kit from Industrial Test Systems. I checked the accuracy of the test kit on my unfiltered water since I knew from professional testing that it contained 12 ppb. The kit, model Quick II #481303-5, seemed dead on in detecting the 12 ppb in the unfiltered sample. BTW, I do not recommend the other arsenic kit from ITS Model #481396-2 as it was much harder to use/read. The filtered sample came in at approx. 7 ppb. I can report that my water flow rate at the kitchen tap, through this filter, is as strong as ever. Because this is a combination carbon and resin (KDF) filter, there will be some carbon fines that flow out upon initial start-up, but this dissipates after a few minutes of flow. I''m giving this cartridge 4 stars since I was mildly disappointed that it didn''t do better in removing my arsenic; however, it did reduce my arsenic from 12ppb to 7ppb and for that I''m glad. I will probably try a different, more aggressive cartridge next; perhaps, one that uses iron oxide media or some other arsenic specific resin. I''ll update this review once I''ve done this.