How to clean a Home Made RO system

[rlapointe]

Hi,
I bought the components to make myself a small RO system at the end of last year and have been experimenting with it with water (until the sap start running hopefully tomorrow :(). My question is about how to clean my system as I plan on running the RO every couple days. 1. Between runs. 2. At the end of the season and 3. For preservation of membranes until the following season. After much reading, it looks like a 1% solution of SODIUM METABISULFITE should be used for long term storage (in the fridge). But looking at my online store of sugaring equipment, I also see CITRIC, CLEANER OXYSAN and MEMBRANE SOAP. Could anyone tell me when to use each and in what concentration?
Thanks

[Daveg]

1) Do not expose your RO to below freezing temperatures. You will ruin the membranes and crack the tubing, housings or pump parts.
2) Store your RO some place cool and dark between runs. Whether or not to clean it between runs depends of several factors. How long between runs? How dirty did it get?
3) Between seasons use Na2S2O5 at 1% concentration as a flush and store the membranes in a refridgerator.

[Bricklayer]

What membranes do you have?

[bowhunter]

As stated earlier. Make sure you protect the membrane from freezing.
1. Flush the membrane with permeate for a least an hour after each run. If you can warm up a few gallons of water or permeate to flush for 10-15 minutes in addition to the regular cold permeate flush, even better. Do not exceed 114F during a warm water rinse. Higher temperatures can damage the membrane.
2. You will probably need to do a soap or lye wash every 4-5 runs. I almost never do a soap wash until after my season is over.
3. The soap is specific to your membrane. Probably Membrane Soap is what you need. During the soap wash the pH and temperature are critical to safely cleaning the membrane. Do not exceed 114 F with just water. Each membrane has different pH and temperature limitations so you need to know which membrane you have. Generally the nano-filtration membranes need milder conditions. An xle for example can be cleaned at 12 pH and 94F.
4. A 1% solution of sodium metabisulfite is the storage chemical. It will work fine if you store the membrane at room temperature. I've had good luck with it for several years on the same membrane. I have a membrane holder made out of pvc pipe.

[hodorskib]

Here are some directions they have worked really well for me.
https://sites.google.com/view/mattatuckmadnessmaplesyrup/cleaning-and-storing-ro-membranes