Commercial pure water machine is generally configured with five stages. The first stage is PP, the second one is granular activated carbon, the third stage is compressed activated carbon, and the fourth one is reverse osmosis membrane(RO membrane),and the fifth stage is post-T33.According to the normal water pressure and water quality, the filtration accuracy of PP  is usually 1 micron or 5 microns, and its life is 3-6 months; Generally, granular activated carbon is measured by iodine value. The common iodine value of carbon in the market is 800-1000, abbreviated as UDF, and its life span is 6-12 months. Compressed activated carbon is made of excess pulverized carbon by compression cleaning and calcination. Also known as a carbon stick, or CTO, it has a life span of 6 to 12 months.RO membrane originated from American technology, the desalination rate is 99%, conversion accuracy is 1/10000 micron, its life span is about 2 years. According to the styles of commercial pure water purifier, there are ordinary commercial machine and luxury commercial machine. The filter element level and filtration principle are the same between these two, but the price and circuit layout are quite different, especially the circuit of the commercial pure water machine from different manufacturers are quite different, which leads to the difference of working efficiency even the same name and shape, it is the different internal structure.