Bests & Worsts Reviews from Amazon

I used a TDS (total dissolved solids) tester on my tap water in Southern California the results were 442 ppm (parts per million) When I tested my refrigerator water using this new filter the results was 310. This is marginally acceptable for a water filter and to me a total rip off for this expensive filter. My reverse osmosis filter results are 57. 57 is good enough water for me to drink but not 310 when the filter is new and only getting worse over time