RO membrane flushing

[Redman88]

so I am wondering if a post use flush is necessary for an RO membrane, if a preflush is conducted.

[rekab]

Look up info on kinetico RO systems - it wasn't built for reef use but has an amazing flush system that's automated after each time it runs. Keeps the membrane running much better. Not a direct answer but the philosophy behind the flush system can be implemented to lengthen the useful life of your system.

[Redman88]

not very helpful as it looks like they don't sell their flush system by its self, not that there is a lot of info about it on their site

[Bpb]

The purpose of the flush is to save on Di resin more than membrane life. The membrane gets destroyed by chlorine. When it sits for a while it'll send a high tds burst of water to the di resin for the first few minutes of running. Called "tds creep". The flush helps reduce the amount of water going through the Di resin and diverts most of it straight to waste until it flushes away that high tds buildup on the membrane. Once the post membrane tds drops to an appropriate number, then we shut the flush off and resume normal operation.

Running the flush after use won't really reduce the tds creep you encounter while it sits. It's most important to just run the flush before ise

[Redman88]

You can also stop the burst to the DI by diverting the output of the RO membrane to waste for the duration of the flush.

[Redman88]

Also forgot to ask does a booster pump (if you need one) need to be on for the membrane flush?

[Mark9]

The purpose of the flush is to save on Di resin more than membrane life. The membrane gets destroyed by chlorine. When it sits for a while it'll send a high tds burst of water to the di resin for the first few minutes of running. Called "tds creep". The flush helps reduce the amount of water going through the Di resin and diverts most of it straight to waste until it flushes away that high tds buildup on the membrane. Once the post membrane tds drops to an appropriate number, then we shut the flush off and resume normal operation.

Running the flush after use won't really reduce the tds creep you encounter while it sits. It's most important to just run the flush before ise

Spectrapure says that flushing is most effective right after producing water and filling your reservoir.

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[mrbigshot]

i followed brs's advice and didn't bother with flushing the membrane. i just put a valve before the di so i can fill water jugs for drinking and also discard the first bit of water to avoid burning up the di resin. i'm on 3 years with the same membrane with tds out being 1-2 before the di stage. the first membrane went over 4 years before i changed it.

[Bpb]

That may be the case, but I go off of what my tds meter says more than anything so when I see massive amounts of tds creep when I turn the unit on, I'll flush regardless of advice

[Mark9]

That may be the case, but I go off of what my tds meter says more than anything so when I see massive amounts of tds creep when I turn the unit on, I'll flush regardless of advice

The OP's original question was about what's better, pre or post membrane flush.
Spectrapure recommends post as being better.
I myself do both a pre and a post flush.
You, obviously can do whatever you want.

[Tarawa]

I flush the membranes of my RODI system after use and every eight or so hours when filling a 125g tank. I run the RO into the drain after the flush because you get high TDS water after that, and go back to filling after it reaches the normal levels.