Depends on which one you use. If there are several layers of sand and stones in the transparent cylinder with a price of 30 yuan, I personally suggest not to buy it, because the effect is ok at first, but after a long time, scale will deposit on it, and the water purification effect will not be achieved without cleaning for a long time. And from the point of view of living, it will be more troublesome to clean up soon. A few hundred dollars is better than the last one. This kind of water is used in my home. It was originally said to meet the drinking water standard, but we have never used this kind of water to drink directly. Therefore, it is recommended to order bottled water with better brand. Although there are often problems on TV, they are generally acceptable.