The TDS pen is a tool for quickly detecting the total dissolved solid content. Because the reverse osmosis machine removes 90%-98% of the dissolved impurities in the water, while the ultrafiltration machine filters the particulate impurities, suspended solids, colloids, and other substances in the water, retaining the dissolved substances in the water including calcium and magnesium ions. Therefore, the data measured by the TDS pen is no different from that of tap water and may even be higher than that of tap water.

Unused filter elements: Unused original filter elements should not be unpacked. It is best to store them at a low temperature of 5-10 ℃. When storing in an environment with a temperature exceeding 10 ℃, choose a well-ventilated place and avoid direct sunlight. The storage temperature should not exceed 35 ℃. Avoid storing in a humid environment and avoid water ingress. Meeting the above conditions, the new membrane element can be stored for about 3 years to ensure its service life. If the reverse osmosis machine is not used for 3 days after installation, it is necessary to turn on the faucet to drain and flush. Do not supply water and electricity to the newly installed machine under unused conditions.

The World Health Organization (WTO) Drinking Water Quality Criteria: There is no specific PH index specified, but it is added that low PH has a corrosive effect; high PH affects the taste, with a soapy smell; in order to make chlorination more effective, PH≤8 is preferred. The Drinking Water Quality Standards of the US Environmental Protection Agency (EPA): There is no specific index for Class I water; for Class II water, PH=6.5-8.5 (that is, both acidic and alkaline are allowed, which is relatively宽泛) The Drinking Water Quality Standards of the European Union (EC): PH=6.5-9.5, the minimum value of PH for bottled or barrelled pure water should be reduced to 4-5, and for bottled or barrelled natural water rich in carbon dioxide or artificially filled with carbon dioxide and water, the minimum value should be reduced even further. This restriction on the minimum PH is relatively strict and cannot be high. The Drinking Water Quality Standards of Japan: The PH value is 5.8-8.6, and the lower value is wider. GB5749 Domestic Drinking Water Health Standards in China: The PH value is 6.5-8.5; GB17323 Bottled Purified Drinking Water: The PH value is 5.0-7.0, which is consistent with the standards of developed countries in this regard. Conclusion: 1. Water that meets the standards can be consumed, and there is no such thing as drinking acidic water or alkaline water is good. 2. Stomach acid is a strong buffer solution, no matter what water is drunk, the PH in the stomach will change to acid.

1. The principle of the TDS pen measurement is to indirectly reflect the TDS value by measuring the conductivity of the water. Physically, the more dissolved substances in the water, the higher the TDS value of the water, and the better the conductivity of the water, and the higher the conductivity. Question: Why is the TDS value of purified water measured similar to or even higher than that of raw water, and possibly higher than the TDS value of tap water? Answer: 1. The principle of the TDS pen measurement is to indirectly reflect the TDS value by measuring the conductivity of the water. Physically, the more dissolved substances in the water, the higher the TDS value of the water, and the better the conductivity of the water, and the higher the conductivity. 2. The factors affecting the TDS value include: 1) the impurity content in the water; 2) the temperature of the water (the higher the temperature, the more active the ions); 3) the drop in the electric field in the water (the battery power of the TDS pen); 4) the water flow rate. 3. Ultrafiltration machines commonly use ultrafiltration filters, PP filters, etc. The filtered water is called purified water, which mainly removes sediment, rust, colloid, bacteria, viruses and other substances in the water. If there is an activated carbon filter, it can remove residual chlorine in the water. 4. The ultrafiltration machine cannot filter out the ion content in the water, that is, the number of conductive ions remains basically unchanged, but the impurities mixed with or wrapped around the ions are less, so the activity of the conductive ions is enhanced. Conclusion: It is normal that the TDS value of purified water measured is similar to or even higher than that of raw water, and the temperature also affects the TDS value, the higher the temperature, the higher the TDS.