Incorrect storage.

[thomashansen871]

So, I loaned my RO out last year and I just found out that at the end of the season, the guy just ran permeate through and then set it aside. It has been climate controlled, but do I have to worry about the membranes going bad?

[82cabby]

Yes.
What is the RO configuration? Size, number of membranes, etc. Did you pull the membranes and give them a visual check and a sniff? What do they look like? It’s been my experience that Membranes that are thoroughly rinsed, wrapped up in plastic then refrigerated generally are ok, but stored at room temperature they don’t do great unless they are in a preservative. Also they don’t handle being dried out well.

[thomashansen871]

It is a 2 post 4x48. I just got it back from them and haven't torn into it yet.

[ecp]

Probably this advice changes based on every sugarbush, flows, pressures, minerals, ect. They should be fine. Do a rinse cycle/wash cycle/rinse cycle then try a concentration cycle and test the permeate. There are a lot or larger ROs out there that are just stored in permeate keeping them wet all year.

[thomashansen871]

I plan to run the soap cycle for double the recommended time, I will buy a set of new membranes just to be safe. Thanks.

[Goggleeye]

Probably this advice changes based on every sugarbush, flows, pressures, minerals, ect. They should be fine. Do a rinse cycle/wash cycle/rinse cycle then try a concentration cycle and test the permeate. There are a lot or larger ROs out there that are just stored in permeate keeping them wet all year.
I would agree. I got lazy with mine and then totally forgot to run the preservative through. They were fine, though. Still tested at a good rate and didn't pass any sugars. I would give them a try. You can always get new ones shipped to you in a hurry.