I bought this item based on the good reviews and I thought it would save me money by prolonging the filter life. However things did not go as planned. One of the units broke down less than 1 month of use. Luckily it was still in the return window and I easily got it exchanged. For those who wonder, I did not dip it all the way down , so it was not my obvious fault it broke down. Second one has been working fine in terms of getting on and off as it supposed to but the readings of the same sample within ten minutes is completely different. The variation is more than 10%, so accuracy is questionable. Besides, I change the filter and compare the before and after readings and do not see a change at all. You can say that the filter itself is not working and it may be true, but I feel the difference in taste while this machine sees nothing in numbers. So if I had a second chance, I would not buy this item, yet so far it has saved me nothing at all.