I am absolutely disappointed by this order. After installing the filters and starting an osmosis cycle at 100 degrees, I restarted a cycle and what a surprise after testing the osmosis water with a tds pen: 207 ppm... !!! My old filters, certainly twice as expensive, gave me about 23 ppm at first. Might as well drink the water from the network directly. Is it because I have the "zen & pure" osmosis machine twice as expensive and not the "osmotic"? but they are both made in the same factory I suppose. Are these counterfeit filters? I'm not going to ask for a return and refund, so I lost over £55!