but we've always used brita. it's two stage-filter... doesn't compare to zerowater's 5-stage. this meter shows how much stuff, or dissolved solids, gets left behind. our tap water is 220. brita? 110... seriously? but zerowater- let me guess. zero? yup, that's how i know it is the purest-tasting water. i need to find the receipt for that. oh yeah, you do.