What does RO/DI system mean in practice?
RO removes most of the salt load, and the DI resin polishes the permeate to a very low conductivity, so its capacity is efficiently used.
When does it matter?
Connecting DI without a functional membrane causes rapid depletion of the resin, and TDS itself may not show the beginning of breakthrough of poorly conductive impurities.
Which solutions are related to it?
RO retention and conductivity after DI are monitored separately, resin is replaced before the required limit and water stagnation is prevented.