RO/DI question

[Treebeard]

Apparently my memory is not what it once was, or maybe it never was....anyways my raw water is 276. TDS after the RO membrane is 20.
I did not have time to take a picture, but from the instructions it is a 5 stage system:

1. 5 micron sediment
2. Carbon
3. 5 micron coconut carbon
4. RO membrane
5. DI cartridges (3)

At the beginning it was reducing TDS to 0.
When I changed the carbon and sediment filters, and the DI resin, I did not change the RO membrane, nor did I disconnect and flush the filters.

Is my RP membrane ruined, or can I flush it out? As I said previously, I am also having trouble with the flow restrictor so I guess it is also screwed up. Your explanations would explain the problem.