Can the 40 micron filter the impurities seen by the naked eye? In general, it is OK, because the 40 micron filter plus cake layer can filter 10 microns or even smaller impurities. But if it is true, there is no filtered impurity, but you can't tell that it is a few particles. you can see it in a large amount.
What is the glass ball in the middle of the front filter? That is silicon crystal (compound phosphate), which can be dissolved in water slowly. it is generally used to treat domestic water or to reduce the deposition of water and alkali on the water for heating. But in fact, many manufacturers put this product on the water, so that the dissolved silicon crystal (composite phosphate) will enter the drinking water. There is no long-term conclusion that this will have any impact on the human body.Therefore, it is not recommended to install this kind of glass ball filter at the front end of the catering water.