It's not easy to watch it for you like this. But I haven't heard of this brand you bought.
Since the water purifier is a product related to health, it is recommended to use it well, and you must really rest assured. For example, the water purifier adopted by Li Sheng enterprises in the Shanghai World Expo, or the water purifier produced by domestic membrane manufacturers, is the real water purifier.
Simply teach the landlord some self-testing methods ... 1680, at least with ultrafiltration stick or activated carbon.
You can pour a glass of beer into the water purifier to see if the purified water is still yellow. If it is still yellow, it means there is no activated carbon. Then use ink (for calligraphy, the main component is macromolecular form) to pour into the water purifier. You can put more water to make it dark. See if the water from the water purifier is white and transparent, black or black ... if it is black or slightly black.