We have been Zero Water Filter users for several years now. We have South Jersey coastal well water and it's TDS varies according to season. Our Zero Water Pitcher guarantees us the freshest water possible year round. As for my review title, we have a rescue cat that literally tells us when the water filter needs to be changed! After we give her fresh water she will sit in front of the water bowl and meow her head off when the filter needs to be changed. She usually pegs it at .005 or more. I always compare her opinion it with the provided meter and her record so far is 100%!