Both of us has the original membranes. I bought mine in November and my mate bought his, after seeing mine, in December and yes, the wrappers have been removed and that posting about leaving the wrappers on was a classic.
Interesting about the o rings. I'll phone my mate up tomorrow.
Something I read somewhere a few years ago and I don't know how true it is but it seems to make sense, is that two ro system in two different places may have the same tds output by one will go through resin quicker than the other to maintain zero tds because although the ro tds is the same, what solids are in the ro water can be very different.
That in turn can affect how quickly resin gets used because some impurities are harder to remove than others.
Going by that, the thing is with just going by tds output from any ro, is that the tds value is only part of the story. It's what impurities were in the tap water to start with as two places with the same tds might have completely different impurities in the water and the same for the output.
I think.