XLE4040 Membrane Yellow Wrap Has Bubbles

[Rockrila]

Shutdown my home built RO today and pulled membrane out to see that the yellow wrap had numerous bubbles. Pushing on them, it was hard to tell whether there was liquid or air behind them. I figure it must be liquid as the membrane sank in the storage vessel as usual. RO worked fine all season. Has anyone seen this?

- Bill

[Urban Sugarmaker]

Yes I had this too. In my case it was bacteria releasing gas. Be sure to do a soap wash and store properly in a preservative solution of 1% sodium meta-bisulfite (available online). The bubbles will go away.