How do I tell if my membrane is still good?

[Diesel Pro]

At the end of the season I washed and rinsed my membrane. I left in in my homemade rig and sealed it off. I meant to get back to it and put in into storage solution, but never did. I opened the unit and found it did have a bit of pressure inside, but the liquid did not smell bad. So should I run some tap water through it and if it flows call it good?

Membrane is a XLE4040 I believe.

[Russell Lampron]

Try concentrating sap with it and see if your flow rates are good. I'm thinking that it is okay. I store mine in permeate and my flow rates are still good after 3 seasons of use.

[Diesel Pro]

FYI it works just fine with no sign of slowing down and 0.0 test out the permeate line.

[Diesel Pro]

Running as good as ever. Thinking I'll store in the machine again.

I get .6-.7 gpm from first run sap at about 150 psi. Ramp the psi up a bit as the sugar content rises. I don't have the guts to push past 275 psi and don't see the need.

It is SO nice to boil 15% sap versus 2.5% that we are starting with...