1. Too slow to make water: whether the filter element or reverse osmosis membrane of the prefilter is blocked;
　　2. Too fast water making (filling a bucket in less than an hour) : the reverse osmosis membrane is damaged;
　　3. Poor taste: the life of the post-activated carbon filter is over; RO membrane removal rate less than 75% : the life of reverse osmosis membrane has reached.
　　The calculation formula of membrane removal rate is: RO membrane removal rate =(raw water TDS value - pure water TDS value)*100%/ raw water TDS value
　　This paper is sorted out by dongguan oneness filtration technology co., LTD