[slendersunfish]

Ive been told that i should backwash my second hand 4040 ro with salt to add longevity to the membrane.Is this simply a case of putting salt in a small vessel, adding pressurized water back into the "wrong" side of the 4040 ro ?
Does anyone know

[Smart Carpet]

No, you do not backwash your RO with salt, or with any water for that matter!

If you use Softener Resin then you must re-generate this with normal dishwasher salt before each fill.


With your RO, you should run the water with the waste open fully for 5 minutes before and after each fill*

*unless you have an automatic flush setup which will open the waste gate fully for you for a minute or two every hour that the RO is in use.

[Lee GLS]

SALT WILL KILL YOU RO!!!!!

[Spruce]

A water softner removes the magnesium and calcium ions in the water and replaces them with sodium ions which is kinder to r/o membranes.

So salt water shouldn't damage your r/o membranes. Many desert countries rely on the desalination of seawater via reverse osmosis to provide drinking water.

The water mustn't contain chlorine, as the chlorine is what destroys membranes.

Flush as J WFP has advised using your flush valve and using water that has been passed through your sediment and chlorine block filter.