off season membrane storage

[MapleCamp]

first year with a home built ro, was wondering what others do to clean and store thier membranes. Thanks

[Msboucha]

I do a soap wash with a concentration of water/H2O BioMembrane that matches the chemical cleaning pH level and temperature for my membranes. After flushing all existing sap/water out of the RO, throw all intake/output lines into the same tank of soap solution. Run for an hour or so. Then begin a rinse using either clean permeate that you saved, or in my case well water (some dont recommend this, but our water is good and I havent had an issue). Once the soap is all washed out (you can tell because your pH level will return to that of your plain water), I'll mix up a solution of 1% sodium metabisulfite and circulate it through the RO. I pull the membranes out and store in a PVC vessel I made, adding additional preservative solution to top it off and store it in a cold corner of my basement. Not a bad idea to change the preservative solution after 6 months, though I did not do that last year and things were pretty good. In the spring do a quick rinse, a soap wash, full rinse and start running sap.

[MDR Maple]

I too was wondering about this recently and considered fabbing up a PVC tube for storage of my 3 x 400 gpd membranes. They are 3" outside diameter so I think I would need 4" diameter PVC pipe and fittings. I priced it out at around $30 and was wondering what the value is achieved by storing them this way. I was reconsidering just doing the RO wash of the the RO system, including membranes in their housings, and then preservative and store the whole system, filled with preservative in my basement.

Why store it in the special PVC tube?

[ecolbeck]

I too was considering going the PVC route but I balked at the $30 cost. The most updated instructions for the RO Bucket state that you can store the system intact and filled with preservative. I will try that this year although I am worried that small leaks may drain the system over time. Has anyone else stored their system in this way?

[Msboucha]

Why store it in the special PVC tube?

No issues to store it in the RO, I just drain my RO and store it where it is not heated. The membranes cannot freeze and should be kept cool, so those are stored inside where it doesn't freeze and is cool in the hot summer.

[Russell Lampron]

If you can store your RO where it won't freeze you don't need to remove the membranes and store them separately. For producers with bigger RO's It's cheaper to remove the membranes and store them and drain the RO than it is to heat their RO room all year. I heat my RO room with my OWB and leave the membranes in.

[30AcreWoods]

I have stored my RO Bucket from the end of one season to the beginning of the next without issue. I wash the membranes with the RO cleaner (recirculating it for up to an hour), then do a quick one gallon flush with permeate water and store the entire system with the dilute wash. I don't think small leaks should bite you because those are only likely to occur when the system is pressurized, and the system shouldn't be pressurized after you shut down the pump. I stored the system in my basement where it is cool and there is zero sunlight. When it is sugaring time again, I installed an activated carbon filter (I'm on city water and didn't have any permeate or large volume of distilled water) and flushed the entire system once a day for 10-15 minutes for 3 or 4 days. You can also wash the system at the beginning of the season with a peroxide solution (after flushing the storage fluids). I did that as well as the flush and the system worked flawlessly. You'll know if there are any issues if during your pre-season flush you don't get a steady trickle of permeate flowing.

Whatever you do, don't use chlorinated water as you'll kill your RO membranes. And if you are using clean permeate water for your post season wash before storage, you can eliminate the 5 micron water filter during the washing process - and leave it removed during storage.