In searching for an under-counter water filter for our kitchen sink, I came across a product for a pool that sounds too good to be true. I know, I know, it probably is however....... it's worth at least asking. Has anybody used this product before? The Pool CuZn & Spa CuZn – CuZn Water Filters It's advertised as a chemical free pool treatment that is used in thousands of pools. Anybody heard of it or use it?