Review on Clear2O CWF503: Next-Level Replacement Filtration Technology for Crystal Clear Water by Mark Kolipano

I have an older model CWS100 and noticed that the CFW101 filters out about 60 contaminants compared to 200 for the 503. Wrote customer service and was told it would fit , but I've seen some reviews that question this. I had a little trouble inserting it the first time, but it fits and works well. I had Zero Water and a meter and was surprised to find 101 reading 145 and 503 reading 245. Zero, of course, registered zero. But as long as it filters out impurities, I find water tastes better with Clear 2 0. I hope this helps those who are interested in the 503 filter working instead of the 101 filter.