Old, brand new RO membrane-still ok?

[TJ D]

Hi all,


4 years ago, we started seeing our TDS numbers climb, so I bought a new membrane for our system. It's still in it's original packaging.


We've had good access to water since we let the tropics, so we haven't run the unit at all. Now, it's time to get it going again, but I don't want to install and use the membrane until we actually want to use it, but that'll be right at the start of a transatlantic, so I don't want any surprises, as we won't have time to get another.


So, can anybody tell me if these things have a shelf life if they're unopened? I think that it should be fine, but want to make sure I'm not wrong on that.



Anybody got a definite answer?



Thanks much, TJ

[TJ D]

After a call to Katadyn-it sounds like you guys might need some more info. This is a Spectra system. It seems to matter to them, I'm not sure why.

[mvmojo]

As long as the membrane is sealed and hasn't dried out you should be good to go. Fire it up a couple weeks before departure to test. If you're not happy with the product water, order a new membrane then. They're not scarce so you'll have plenty of time to receive and install it.

[bdbcat]

Anecdotal data point:

Found a 40" membrane in a garage sale. Sealed, still clearly wet with preservative inside the package. Date code said 9 years old. Paid $10.
Installed, worked perfectly. Still works fine, producing specified TDS numbers.

YMMV

Dave

[TJ D]

Thanks, guys. I'll chuck it in and see how it goes.

TJ

[CarinaPDX]

What TDS numbers would you expect? What would be the normal range, and what the maximum for drinking? I have some old membranes, which may have dried out; what could be used as a wetting agent? Thanks


Greg

[SV THIRD DAY]

Originally Posted by CarinaPDX

What TDS numbers would you expect? What would be the normal range, and what the maximum for drinking? I have some old membranes, which may have dried out; what could be used as a wetting agent? Thanks


Greg

A new membrane should start out around 100-140ppm.
Then start it's slow death in 5-7 years until it hits 500ppm and you replace them.

Contrary to dock rumors membrane do not have a shelf life....BUT if they dry out they are DeAD and if they are stored above 140-deg F they are DEad. But as long as they are stored properly (which sometimes how do you know) then age isn't a big deal.

[CarinaPDX]

OK, thanks for the info. Too bad there is no wetting agent to revive them (assuming no growth).

[Minggat]

Originally Posted by SV THIRD DAY

A new membrane should start out around 100-140ppm.
Then start it's slow death in 5-7 years until it hits 500ppm and you replace them.

Contrary to dock rumors membrane do not have a shelf life....BUT if they dry out they are DeAD and if they are stored above 140-deg F they are DEad. But as long as they are stored properly (which sometimes how do you know) then age isn't a big deal.

I commission large scale desalination plants. Over 40 years at it. At one plant someone had opened several of the plastic bags that the membranes come shipped in. Read bone dry by the time I arrived one year later. Many months still later the facility got in a pinch and I had to install those membranes. To my surprise they performed as new. Now the industry has evolved to where some membrane manufacturer ship membranes dry.

Point is, don’t be to quick to throw out dried out membranes.

[Minggat]

Originally Posted by CarinaPDX

OK, thanks for the info. Too bad there is no wetting agent to revive them (assuming no growth).

Try water as a wetting agent. 😊 Not trying to be funny, just saying. It has worked.

[TJ D]

BREAKING NEWS...


I stuck in the old one today, and everything looks great. My TDS meter is dead, but the water tastes perfect. I think the prolonged storage had no ill effect. Nice!

[a64pilot]

You must test it, you cannot go by taste, even very high as in unsafe to drink salinity water, will tase fine.
Testers are of course very cheap, about as much as a flashlight, get a spare too.
$6. https://www.amazon.com/TDS-Meter-Pro..._12_sspa&psc=1

[Jon Hacking]

DON'T rely on taste. You won't taste 800ppm water, but your kidneys won't like it for long. TDS meters are cheap.


Several months ago we noticed our TDS numbers climbing, so we ordered a new membrane (2540, for Spectra). The membrane was shipped & stored (& advertised as) dry. Only recently installed it, & it seems to be working fine. But I don't know if (or how) dry membranes are different from the older wet membranes.

[Oceansailor]

Originally Posted by Jon Hacking

DON'T rely on taste. You won't taste 800ppm water, but your kidneys won't like it for long. TDS meters are cheap.


Several months ago we noticed our TDS numbers climbing, so we ordered a new membrane (2540, for Spectra). The membrane was shipped & stored (& advertised as) dry. Only recently installed it, & it seems to be working fine. But I don't know if (or how) dry membranes are different from the older wet membranes.

I agree that a cheap TDS meter is a no brainer. I disagree that you would not taste salinity as high as 800.

[belizesailor]

Originally Posted by Oceansailor

I agree that a cheap TDS meter is a no brainer. I disagree that you would not taste salinity as high as 800.

I dont really need a TDS meter, Ive got my wife! [emoji1787]

She can taste amazingly small changes in water quality.

Me, I need the TDS, but she is the final test for any issues.