Winterizing RO membranes

[phorvati]

Any ideas on how to get Propylene Glycol-100 to the product side of the membranes?
I plan on running few gallons of PG-100 through the brine side plumbing, but I am not sure if antifreeze will make to the product side, and if not how do folks get it there?

[Tellie]

Simply pickle the system as you normally would with the PG-100. You don't want to pressurize the system during pickling so the solution is forced through the membrane surfaces into the product side. Some will naturally leach through anyway. Pickling is to stop growth on the surface of the membrane. You will get all the freezing protection you'll need from a simple pickling procedure. The only other option would be to remove the membrane and place it in a sealed 4" PVC pipe with PG-100 and storing it on end. But don't worry it will be fine just pickling it normally with PG-100 with the membrane in the system.