Ro pressure vs TDS

[maroun.c]

Any info or links to any explanation why when running RO at a lower pressure the TDS goes a bit higher than when Rao runs at higher TDS?

 

[BoSalman]

Any info or links to any explanation why when running RO at a lower pressure the TDS goes a bit higher than when Rao runs at higher TDS?

It has to do with membrane rating.

The pressure rating on a membrane is the rate which is required to pass the tap water (forcebly) into the membrane itself to filter it out. When that pressure drops, some water will not make it through the membrane, but across it, and thus escaping that filter stage.