ph of membrane cleaning

[s&s syrup]

what should the ph of the wash solution be for a nf 270 membrane

[MT Pockets Producer]

I'm not sure what unit you are running but this CDL manual has some info in it. Page 11 shows the ph and page 14 shows that it is an NF 270. Hope that helps.

http://www.cdlusa.net/Data/Sites/8/media/owners-manual-hobby-ro.pdf

[bowhunter]

Per Filmtech an NF 270 should be cleaned at no more than 11 pH and a maximum of 95 F or 12 pH at a maximum of 77 F.

[Russell Lampron]

what should the ph of the wash solution be for a nf 270 membrane

I have read and been told ph 9 is the number but read below as the wash temp also comes into play.


I'm not sure what unit you are running but this CDL manual has some info in it. Page 11 shows the ph and page 14 shows that it is an NF 270. Hope that helps.

http://www.cdlusa.net/Data/Sites/8/media/owners-manual-hobby-ro.pdf

This manual says ph 9.5 at 30*C or the N 270.


Per Filmtech an NF 270 should be cleaned at no more than 11 pH and a maximum of 95 F or 12 pH at a maximum of 77 F.

I have also read this before. My RO shuts off at 42*C which is roughly 107*F. So my conclusion is anywhere between ph 9 and ph 12 is okay as long as you know what your water temp is going to be. I've been cleaning mine in the ph 10.5 to ph 11 range with no sugar passage problems. When I tried to stay around ph 9 the membrane wouldn't get clean.

[markct]

What happens if you wash them too much ph? I have nf270 membranes and used a different brand of soap, it's sodium hydroxide from mes, put the same amount in I always did with cdl savon soap, well now my membranes flow better than I recall or atleast have in a long time did I damage them? Or just clean them like they needed?

[Russell Lampron]

What happens if you wash them too much ph? I have nf270 membranes and used a different brand of soap, it's sodium hydroxide from mes, put the same amount in I always did with cdl savon soap, well now my membranes flow better than I recall or atleast have in a long time did I damage them? Or just clean them like they needed?

Cleaning an NF 270 with too high of a ph opens up the pores in the membrane and that is why it flowed better. I did the same thing when I first started using the NF 270 membrane. After the first wash it flowed better than when it was new. The pores should close up after a couple of days soaking in permeate. Check for sugar in your permeate.

[markct]

I did the test with hydrometer and zero, boiled it down to 4 times and still nothing I can read on the sap hydrometer so I guess I'm ok. Scared me a bit, although at the age of these membranes it's ok if they die

[Russell Lampron]

I did the test with hydrometer and zero, boiled it down to 4 times and still nothing I can read on the sap hydrometer so I guess I'm ok. Scared me a bit, although at the age of these membranes it's ok if they die

Maybe you did just get them cleaner. Did they flow better than new?

If you can, use a refractometer instead of a sap hydrometer to do your testing. They're much easier to read and they are reasonably priced on Amazon and ebay.