Off-Season Storage of Reverse Osmosis Machine... should the tubing be dry?

[fireant911]

Because our syruping season has come to a close, it is time to hibernate the Reverese Osmosis machine! Mine, like many others here, is a home-built version utilizing the AquaTec 8852 pump, a five-micron sediment filter, and four 150 gpd membranes. I have flushed the machine, performed a RO soap wash for one hour (pH at 11), followed by a through flushing until the pH level returned to the level of water, then recirculated using Citric Acid (pH at 2.5) for another hour, and finally flushed until the pH reached that of water again. The four membranes were removed and stored with preservative (Metabisulfite Sodium) inside PVC tubing. I think that this is the recommended preparation activities for cleaning prior to off-season storage.

I have a question regarding the 'tubing' on the machine itself. Liquid still remains in much of the tubing AND because microbial growth does not require but a trace of any leftover / trapped sap or any contamination for that matter, I am unsure if I should attempt to remove this remaining liquid and permit complete air-drying of the tubing? Simply capping of the lines from atmospheric oxygen probably is not a good choice because of the likelihood of anaerobic bacteria growth(?).

Someone had stated earlier that their AquaTec 8852 stopped pumping because it was their understanding that the diaphragm to designed to stay wet during periods of non-use. This may or may not be true because, unfortunately, there is MUCH incorrect information out on the internet... heck, I am wrong a LOT but I am trying to learn!!! I would be very interested to know if others have any experience in one way or the other regarding proper off-season AquaTec 8852 pump storage (wet / dry... or does it even matter?).

[Galena]

I don't RO, but think it would be best to ensure everything is completely clean and bone-dry before you store it. Microorganisms don't need much moisture to get a foothold and begin multiplying.

[ecolbeck]

Go to RO Bucket or CDL Nano website and check out their end of season storage directions.

[Bricklayer]

Once we are done for the season I do all the cleaning and flushing. Then i mix up the Sodium metabisulphate mixture in the wash tank and just turn on the feed pump and let it circulate through the entire system for 10 minutes or so.
I then take my membranes out and put them in the storage canisters and add more sodium metabisulphate mixture untill the membrane and canister will not take any more.
I now know that my RO and membranes have been treated with it and nothing will grow in it. Most of the time there is still a significant amount of liquid in it when I get it back out in the spring. Never had anything nasty grow in it at all.
This year I’m going to be storing mine in an unheated building so it will be the same process. But I’m going to have to run antifreeze through the RO after the membranes are out and drain it.

[82cabby]

I remove the 8852 from the RO cabinet after the final rinse and store it in my basement. It just finished its 8 th or 9 th season on the original diaphragm.

[fireant911]

Thanks fellow syrupers!!! With the plethora of practically instant search results, it is hard to distinguish realistic 'best practices' from someone, like me (very much a novice), 'one-time' experiences. Prior to posting my question, I did look at the RO Bucket site but was a bit confused as they recommend 'dry' for long-term storage of the unit; however, also stated was the membranes are to stay full of water (presumably while still connected to the rest of the apparatus)... I understand the preservative bit but found the instructions lacking on clarity - so, it is wet OR dry storage?

One thing I will definitely be following is leaving the sediment filter TOTALLY empty and dry. I had read somewhere that the new five-micron filter used for soap & acid washing was safe to leave in place during storage since it couldn't be contaminated (I used many gallons of distilled water for the RO Soap & Acid washing and rinsing)... upon taking my machine out of storage this year, something very nasty had grown on that five-micron filter - this is what started my initial inquiry.

I did disconnect all the push-fittings, allow as much gravity drainage as possible, and blew out all of the tubing and fittings with compressed air. After letting it remain apart for a couple of days to facilitate any additional evaporation of droplets adhering to the walls, I will reassemble totally dry and wait until next year's season to commence. 82cabby - thanks for sharing your snippet about your storage practices for the pump as that was causing me grief (as I certainly did not want to ruin the pump's diaphragm by storing incorrectly which is also something I had read).

I think the major take-away here for me is to be careful about what I read!!!

[82cabby]

82cabby[/B] - thanks for sharing your snippet about your storage practices for the pump as that was causing me grief (as I certainly did not want to ruin the pump's diaphragm by storing incorrectly which is also something I had read).D

��. I’ve had great luck handling it that way. But, fwiw, can’t source a replacement diaphragm for that pump. That pump has a 3 degree cam and the only replacement diaphragm I can find is for the 8800 which is 2.5 degrees.