Is it safe to use an old RO membrane?

[Cannoy]

Years ago I bough a 150gpd RO/DI unit from BRS, but shortly after that I read somewhere in the forums only running one RO membrane is best, so I took one off the filter.
The other membrane has been sitting in the canister for years and when I just opened it there was still water and dampness inside. It's currently hooked up to the filter and I'm getting 3ppm coming out of it, so is there any reason why I shouldn't use it?

 

[BryanM]

Do you have a way to test TDS, if so make some water and test it.

My personal view is that they are not that expensive, and water is the heart of what we do, so when I got a rodi unit 2nd hand I replaced everything.

 

[Cannoy]

Do you have a way to test TDS, if so make some water and test it.

My personal view is that they are not that expensive, and water is the heart of what we do, so when I got a rodi unit 2nd hand I replaced everything.

The TDS when I first hooked it up was 3ppm coming out of the membrane and since its been flushing it has dropped to 1ppm.

 

[BryanM]

The TDS when I first hooked it up was 3ppm coming out of the membrane and since its been flushing it has dropped to 1ppm.

I think the general consensus is 1-3 is safe, some say 4.

IMO, 2 is max for me. I just feel that our water is key....