Freezing Membrane

[Amber Gold]

I'm new to RO and forgot about my membranes in the SH until this morning. We've had a handful of nights below freezing...mid-20's the lowest. I pulled the membranes out of the storage canisters and there was some slush and a little ice on the membranes. Are the membranes ruined and how can I tell if they are?

Thanks

[Mark]

Dow website says that you have to thaw them out before using. I froze some real bad a few years ago and they were OK.

[tuckermtn]

josh- might need to check and make sure your pumps/gauges/valves are okay- if there was water in there they might have issues...

[Amber Gold]

The RO machine is all drained with the drains all open. The membranes were stored in PVC storage tubes with some kind of liquid in there...guessing a preservative.

[Tmeeeh]

I heard that any freezing of the membrane material will damage it and will then pass sugar. I was also told that freezing doesn't damage the membrane itself but a drained out but still damp membrane element will contract and crack the permeate tube and pass sugar that way. I used an osmonics machine for 12 years and let the drained out machine freeze every year and never had a problem. I hear that some people are successfully allowing the 8X40 membranes to freeze all winter. I haven't dared try it myself.

[Amber Gold]

The storage tube was only partially filled with preservative.

I was told by the previous owner the membranes together would do about 180 gph, didn't pass any sugar, and are on their last leg. I was hoping to squeeze another year out of them, but maybe now I don't.

[Justin Turco]

Slush? I'll bet they're fine. I ruined a guage one time. The rest of the machine had leader's antifreeze, but it didn't make it to the gauge. I'm keeping my RO inside in the winter from now on.

[maplwrks]

Just bring them in to a warm place. I think they will be fine. It's not like you froze them solid. When you start up in the spring, check them for sugar passage.

[Amber Gold]

That's what I was hoping to hear. It's been below freezing before, but I'm pretty sure it didn't get any colder than the morning I remembered about them. They've been in the house since.

Thanks.