Dear Sir,   I confirm what ...

Dear Sir,

I confirm what other people have written. It is not unusual to see an increase in permeate TDS after a cleaning. If you want to avoid or minimize this effect you could use a neutral pH cleaner. Please contact me by email if you would like to know more about the product(s) we can offer in this perspective.

As a side note; it is generally recommended to first do a high pH clean before a low pH clean. The opposite has a higher probability to leave fouling or scale in your system after the cleaning cycle. In addition, the negative impact on the salt rejection of the membranes (causing the increased permeate TDS after a CIP) is mainly caused by the high pH clean. Finishing with a low pH clean can help restore the salt rejection and prevent or lower the increased TDS effect in the permeate after CIP.