Cleaning 4040 Membranes

[SmellsLikeSyrupNH]

Really trying to do this right so I don’t mess up my new membranes.

A few questions....clean membranes running neutral water (distilled or permeate) should have a PH of 6-7 approximately. When running sap, how do you determine your membranes are dirty and need a soap wash as opposed to just a rinse?

Spoke to Clayton at MES. He said I should mix my soap to a PH of 11. Run it through the membranes and keep an eye on it as it may drop. I did that yesterday and then ran about 75 gallons of permeate through the membranes to rinse the soap out. Got them back to a neutral PH of 7.

Is that how everyone does their rinses, cleaning, and tests?

Thanks!

[Russell Lampron]

You can tell that your membranes are dirty when the permeate flow slows down. It is normal for it to slow down when you do a second pass so don't confuse that with being dirty. When it slows down flush about 50 gallons of permeate through it and if the flow rate should come back. If it doesn't it needs to be cleaned.

I normally do a soap wash on mine after every use. I'll sometimes do just a rinse if I didn't run much sap through it. After I do a wash I run all of the permeate that I have, usually about 500 gallons through the machine to rinse it. I get the 6 to 7 ph reading after running 50 to 75 gallons through it but would rather give it a real good rinse just in case.

When a soap wash doesn't bring the flow rates back I'll do an acid wash. I hate doing those when the sap is running because the RO has to sit for 24 hours with the acid in it.

[SmellsLikeSyrupNH]

Thanks Russell, I appreciate it.

[3% Solution]

Hey Russ,
Somewhere I remember hearing or reading that whatever your RO size is you should run that amount of permeate through it for a rinse after a wash …
If it's a 150/hr. … run 150 gallons through it ..
That sound right ??

[SmellsLikeSyrupNH]

What I did the other day is ran my permeate, recirculating, for about a half an hour for a good rinse. Then I ran a soap wash until the pH was 11, then I did a rinse again in until it got back down to 7PH and emptied my permeate tank.

[3% Solution]

Yeah I just let all 120 gallons go through it

[Russell Lampron]

Hey Russ,
Somewhere I remember hearing or reading that whatever your RO size is you should run that amount of permeate through it for a rinse after a wash …
If it's a 150/hr. … run 150 gallons through it ..
That sound right ??

I think the rule of thumb is you want 2x the size of your RO. Mine is a 250 so 500 gallons of permeate.