You may buy them thinking that these pens can quickly determine the quality of their home water.
In China, the TDS of tap water is generally 100~300mg/L. Groundwater typically has higher mineral content, so its TDS is also higher. In rural areas of Chaoshan, people mainly use stream water or spring water from mountains as daily drinking water, which has low hardness.
TDS primarily reflects the overall level of dissolved minerals in water, and its value mainly affects water’s taste. If TDS is extremely low, the water tastes flat and tasteless. That’s why some users of ChengrongEra water purifier choose our mineral-like water purifiers, because they find water from pure water machines unpalatable.
From my experience, TDS values below 300mg/L are suitable for drinking. However, Professor Shu Weiqun from the Army Medical University, a leading expert in China’s water health field, states in her book Drink for Nutrition: Demystifying Drinking Water, Minerals and Health that water with a TDS of 50~300mg/L tastes good, 300~600mg/L tastes best, and values higher than that are less suitable for drinking. When TDS exceeds 500mg/L, water is prone to scale buildup, which shortens the service life of home water-related appliances.
In Guangdong, water has low TDS and rarely causes scaling. However, stream water from mountains in rural areas often turns into yellow muddy water, which can severely damage home water appliances. This is where whole-house water purification comes in, it not only ensures drinking water safety but also provides comprehensive protection for washing machines, water heaters, and water pipes.
For whole-house water purification, regardless of water quality, the most effective options currently are external-pressure micro-ultrafiltration membranes and internal-pressure ultrafiltration membranes.
Other options like steel mesh pre-filters or PP stacked disc pre-filters have too low precision to filter particulate impurities. PP cotton large white filters have slightly higher precision but still can’t filter fine particulate impurities. Over time, they may even become secondary pollution sources, the more turbid the water, the worse this secondary pollution gets.
External-pressure micro-ultrafiltration membranes, with a filtration precision of 0.1 microns, can completely intercept fine particulate impurities in water, earning them the title "nemesis of yellow muddy water." Though they can’t block bacteria or viruses, their filter elements can be regularly hand-washed, preventing them from becoming secondary pollution sources. They also have a long service life, ChengrongEra external-pressure micro-ultrafiltration membrane elements come with a 5-year warranty.
Internal-pressure ultrafiltration membranes have even higher precision (0.01 microns) and can intercept not only particulate impurities but also bacteria and viruses in water. Typically, those who choose internal-pressure ultrafiltration for whole-house purification are affluent people who pursue a high quality of life and prefer not to bother with manual cleaning.
If the TDS of surface water is abnormally high, it may indicate chemical pollution. The mineral and trace element content in an area is relatively stable; a sudden increase suggests other substances have dissolved in the water, raising the possibility of toxic substances being present.
Therefore, we recommend regular water quality testing for unregulated water sources. TDS pens only indirectly reflect the content of minerals and trace elements in water through its electrical conductivity, and their precision in measuring total dissolved solids is not as high as we might think.
Chengrong Ultrafiltration，Zero Worries for Customers
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Mr. Zhuang Beikan, born in the 1970s, a Chaoshan native and a self-made entrepreneur with 18 years of startup experience.
Chengrong Ultrafiltration Factory has specialized in stainless steel pipeline ultrafiltration water purifiers for 18 years. With 280 colleagues, we focus solely on perfecting one core product. Renowned as one of the top 3 factories in the industry, we stand as a full supply chain factory rarely matched in the pipeline ultrafiltration water purifier sector. Many first-tier water purifier brands, both domestic and international, after extensive searches, ultimately choose to cooperate with Chengrong Ultrafiltration Factory, simply because we can make them zero worries.
In 2025, Chengrong Ultrafiltration Factory finally launched its own brand, ChengrongEra, and began entering the consumer market (C-end). This move brings us closer to end-users, we hope to hear their authentic usage feedback, and manufacture better and better UF water purifiers.
For any questions about ultrafiltration water purifiers, feel free to add my assistant Ms. Liu Jinlu on WeChat. I myself don’t understand English, but my assistant is highly proficient in both English and ultrafiltration.
Tel/Wechat of Ms. Liu Jinlu：15988828791
Email: chengrongera2025@outlook.com
