To Flush or To Not Flush... Your RO Membranes

schooleyosis · Sep 2, 2014

A new topic has been burning in my head the past few weeks. :flame:

Who flushes their RO membranes before and after making water? I just replaced my membrane after 2 years of use and now my product water is back at the 90gpd mark and the rejection rate is back at advertised or better. Before I had replaced the membrane the rejection rate was down to 94% from the advertised 98% and my product water rate was way lower than the advertised 90gpd.

So, to increase the life of the membrane this time around, I plan to install a manual flush kit to flush before and after each run. I've heard things about power flushing, reverse flushing, manual flushing, and auto flushing.

I've heard of membranes lasting 5+ years as well. Middle Tennessee has some of the lowest TDS in the country so I am thinking the 2 year lifespan of my membrane was on the low end.

Who does what and who doesn't do what? GO!!!

moulton712 · Sep 2, 2014

I flush for about 5 min, then i wait till the Tds goes down to 1 or lower then place the rodi line into my containers. If you let water sit in the unit there can be Tds creep.

Defective_Weeble · Sep 2, 2014

My BRS unit has the flush thing on it. I've never used it.

joeyhatch11 · Sep 2, 2014

I flush when I'm done. It's always the polite thing to do.

rado87 · Sep 2, 2014

I always flush it before I use the water as my tds meter says the water that has been sat for a week in the unit reaches up to 100tds but run it until reads 0 until I fill up any containers. Never flush after use though as don't see why would need to ?

schooleyosis · Sep 2, 2014

joeyhatch11 said:
I flush when I'm done. It's always the polite thing to do.

Lol

I'm sure the people around you appreciate that.

joeyhatch11 · Sep 2, 2014

I don't flush before because I run it wide open for 3-4 minutes after. Plus I make water every 3 days. 5g here and there, so its not like its sitting for weeks on end before the next useage.

Reef Junky150 · Sep 2, 2014

I run my ro/di straight to float valve in my sump. Their for it gets used a little a lot of times during the day plus twice a month for wc. I backflush mine for a few minutes every week when I clean skimmer cup. Have never not done it to see what difference if any it makes, just have always done it

Reef Junky150 · Sep 2, 2014

It runs to float valve in my sump for auto top off to clarify.

schooleyosis · Sep 2, 2014

Reef Junky150 said:
I run my ro/di straight to float valve in my sump. Their for it gets used a little a lot of times during the day plus twice a month for wc. I backflush mine for a few minutes every week when I clean skimmer cup. Have never not done it to see what difference if any it makes, just have always done it

How to back flush the system? Is it as simple as hooking the waste water line and the supply water lines up backwards?

TankedNTn · Sep 3, 2014

I flush mine for at least a couple minutes before each use. Mine cam with the flush valve on top of it.

TitansFan · Sep 3, 2014

You should be flushing afterwards. The flushing is meant to remove unfiltered water sitting on the membrane that would evaporate and leave impurities that lead to clogging the membrane.