The NuAqua system is the second system I've owned. I bought one prior to that on Amazon at a higher price and worse performance. I've tried several different RO membranes, and none of them have worked very well. I got 90-93% filtration with 420-460ppm tap water and then it would degrade quite a bit over time. The NuAqua membrane is giving me a 95-97% reduction is measured ppm, and the degradation over time is much slower.