What does diaphragm recoil mean in practice?
Salt retention is calculated from the conductivity of the feed and permeate after the temperature and flow have stabilized.
When does it matter?
The result depends on the type of ions and operating conditions, so a single TDS reading without a feed sample does not evaluate the membrane.
Which solutions are related to it?
Samples are taken simultaneously, the percent reduction is calculated and the trend is compared after excluding pressure, temperature and bypass.