上一期我们跟大家聊到了家用净水器滤芯的种类和作用，这一期我们介绍家用净水器的购买误区和滤芯选择。
In the last issue, we talked about the types and functions of filter cartridges in household water purifiers. This time, we introduce the misunderstanding of purchasing household water purifiers and selection of filter cartridges.
净水器挑选的误区：
Misunderstanding of water purifier’s selection:
误区一：超滤比反渗透好，或者反渗透比超滤好
家用净水器目前以超滤和反渗透两种技术为主，净水器里主要的膜（第四级）就是超滤膜或反渗透膜。
超滤膜可有效去除水中绝大多数污染物及部分的矿物质元素，包括悬浮颗粒物、胶体、细菌、病毒、胶体、大分子有机物等。
反渗透膜可过滤水中所有物质，包括水中天然含有的矿物质元素。过滤出来就是纯净水。
1.ultrafiltration is better than reverse osmosis, or reverse osmosis is better than ultrafiltration?
At present, ultrafiltration and RO reverse osmosis are the two main technologies of domestic water purifier. The main membrane (the fourth stage) in the water purifier is ultrafiltration membrane or reverse osmosis membrane.
The ultrafiltration membrane can effectively remove most pollutants and some mineral elements in water, including suspended particulate matter, colloid, bacteria, virus, colloid, macromolecular organic matter, etc.
The RO reverse osmosis membrane can remove all substances in water, including mineral elements naturally contained in water. The permeate flow is pure water.
误区二：价格越贵过滤效果越好
市场上会有一些厂家投机取巧，用超滤机冒充反渗透净水器，并且标上较高的价格。我们在前面已经说过，超滤和反渗透不存在优劣之分。因此，不能只看价格，应该看使用的滤芯。
越贵的净水器过滤效果越好，这是不对的，所有净水器的运行原理都是一样的，过滤的效果取决于净水器滤芯。
2. The more expensive the price, the better the filtering effect?
There are some manufacturers in the market remark ultrafiltration machine as reverse osmosis water purifier, and marked a higher price. As we have said before, There is no distinction between good and bad of ultrafiltration and reverse osmosis. Therefore, we should not only look at the price, but also the filter cartridge they used.
The more expensive the water purifier, the better the filtration effect? This is totally wrong. The operation principle of all water purifiers is the same. The filtration effect depends on the filter element of the water purifier.
误区三：不用换滤芯的比较好
不管多贵的滤芯，用久了都是得换的!许多广告都说着“不用换滤芯”的净水器，实际上根本不存在。稍微了解净水器的人都知道，水中的泥沙杂质过滤半年或一年就会被塞满整个滤芯，如果到这时候如果还不换掉，那么整个净水器也就报废了。
3: No need to change the filter cartridge means better?
No matter how expensive the filter cartridge is, it has to be replaced after a long time! Many advertisements say that the water purifier "no need to replace the filter cartridge" which is totally fake. Anyone who knows a little about the water purifier should know that the whole filter cartridge will be filled with impurities for half a year or a year. If it is not replaced at this time, the whole water purifier will be scrapped.
误区四：使用寿命=更换周期
这是典型的偷换概念，商家用使用寿命来忽悠消费者，说净水器滤芯使用寿命可以达到两年，其实，即使有十年的使用寿命，在相同的水质条件下，其更换周期基本是一样的
4: service life = replacement cycle?
This is a typical concept of sneak replacement. Someone use the service life to deceive consumers, saying that the service life of the filter cartridge in the water purifier can reach two years. In fact, even if it has a service life of ten years, the replacement cycle is basically the same under the same water quality conditions.
定期更换滤芯非常重要。
It is very important to change the filter cartridge regularly.
净水器滤芯如何挑选：
PP棉：好的pp棉滤芯表面光滑、缠绕密实，拿到手上掂量一下，很有分量，捏下，看下硬度，一般越重的PP棉硬度越高，捏起来软趴趴的PP棉就是很轻，就没有那种捏起来比较硬的好。因为在同样的水质情况下，越软的PP棉使用寿命越短，更换周期越短。
活性炭：建议挑选果壳类活性炭，行业内被公认最好的活性炭是椰壳活性炭，吸附效果好且安全；另外尽量选择碘值高的，碘值900以上；再者可以打开看看裸的碳棒是否掉灰等等都可以作为挑选活性炭的参考依据。
反渗透膜：主要看脱盐率（净化率）、通量（产水量）两个参数；脱盐率越高，净化率越高，通量越大产水量越大；一般大品牌产品稳定性越好；还有就是外观、包装等。
希望通过上述介绍，大家可以更加了解常用的净水器和选择净水器滤芯。
How to select the filter cartridges:
PP filter: the surface of good PP filter is smooth and tightly wound. When you weigh it in your hand, it has a lot of weight. Pinch it and look at the hardness. Generally, the heavier the PP filter is, the higher the hardness is. Because in the same water quality situation, The softer the PP filter, the shorter the service life and the shorter the replacement cycle of it.
Activated carbon: it is recommended to select the shell activated carbon. The best activated carbon in the industry is coconut shell activated carbon, which has good adsorption effect and safety. In addition, try to select the one with high iodine value, which is above 900. In addition, open the bare carbon rod to see if it is ashed. All these can be used as the reference for selecting activated carbon.
Reverse osmosis membrane: it mainly depends on two parameters: salt rejection rate and flow rate; the higher the salt rejection rate is, the higher the purification rate is, the greater the flow rate is, and the greater the water yield is.
I hope you can know more about the commonly used filter cartridges and water purifiers.