What could be the possible reason for the sudden decrease in resistivity of the ultrapure water machine?

Sudden decrease in resistivity is usually caused by the following reasons: 1. Sudden change in inlet water quality (such as an increase in TDS); 2. RO membrane aging or damage (used for more than 2-3 years); 3. Abnormal operation of EDI module (check voltage and current); 4. Terminal filter blockage or expiration; 5. Bacteria grow inside the system. Suggest checking the data of each monitoring point first. If unable to make a judgment, you can contact after-sales remote diagnosis.