Back Flushing Your RO/DI Unit-Filters, etc..-3reef Forums

Diver_1298 · 01-18-2007, 09:40 AM

Ok, I have a question for everyone who owns a RO/DI filter.
How often and for how long do you back flush your Reverse Osmosis membrane?
I usually flush mine every time I hook it up which is about every 2 weeks and run it backwards for about a minute or two. But, I was wondering if anyone actually read the directions and has a good answer for me

Thanks for any replies.

Jim

inwall75 · 01-19-2007, 07:39 AM

Good question Jim.

I think my instruction manual said something generic like "Backflush regularly". Hmmm, does that mean monthly, does that mean daily, etc.

Unfortunately, most RO/DI units don't come with the backflush kit even though you can order it as an inexpensive add-on. I found a flush valve kit here Aquadirect :: RO Filters :: Kent Marine Filters :: All Kent Marine Products for $13.89 but you can get them so many other places (this is just the one that popped up first). If you have high TDS water where you live, adding this flush valve will greatly extend the life of your RO membrane.

With that said, the answer to your question is going to be different for everyone. My incoming water is at 350 TDS so I backflush my unit for about 1 minute at least weekly under normal conditions. If for some reason, I make more RO/DI water that week, I'll flush it again. If your incoming TDS was say 100, you could go longer without backflushing. However, I would recommend weekly just so it becomes a habit.

I'm now curious. How often does everyone backflush and for how long?

milesm4 · 01-19-2007, 08:08 AM

I back flush every three weeks or so, when I do it's for about five minutes or so I usually fill up a watering can for my plants.

jtReef · 01-19-2007, 08:19 AM

Great topic.
I have actually never back flushed.
It has been in use for almost 3 years and was actually running for the last 6 days straight to fill my 180 with 100gal sump with an out put on the tds coming in at 25.
So i need back flush.

Now you have me freaking out though.
When i left his am the water line was at the top and I totally forgot to shut it off. So per my calculations by the time I get home I will have about 20 gal of water covering the basement floor. Not good. I better have those power strips off the floor. :-)

BTW just started sweating.

Tangster · 01-19-2007, 09:19 AM

You do remove and refrigerate the membrane between uses right ? Just backwashing it will not destroy the anaerobic bacteria in there.. Not a good idea to just allow the membrane to set in the cannister and sour and foul up' Also it will detorate the membrane also.. Just FIY you seldom see around and the makers and marketers of the membranes ain't talking. but think about it all the spores and bacteria that the R/O filter catches just and they just set stagnet and breed and grow in numbers hourly. Then you think you are backwashing it but the chlorines will eat up the film and if its well water just more impurities are entering the film membrane.
If it where me I'd backwash it right after you catch new water then put the membranes in a zip loc bag and refrigerate it until next time.. Bst way it to have it solid connected and allow it to empty waste daily to keep it clean and healthy.

m_lacom99 · 01-19-2007, 09:22 AM

Im in the same boat as you jt, never back flushed... I dont really read the instructions on anything so

. I guess ill try to find my manual

.

jtReef · 01-19-2007, 09:44 AM

Interesting Idea Tangster.
I will have to keep that in mind. I typically make RO water every other day and and in batches of 40gal. I also got my RO unit used from a friend so no directions. I had no idea this needed to be done.
So you telling me the best way to clean it is to turn the membrane around and flush it out right? The rest stays the same?

Tangster · 01-19-2007, 09:48 AM

Well maybe you are better off not flushing it really I don't think most have a real concept of how the R/O works .. But unless you store many gallons of R/O water in a holding tank to flush it with and try to back flush it with just normal House pressure its just a waste of time.. Takes very high pressure to realy flush one , Also thats is on a well if on a chlorinated municipal system then a slightest trace or chlormane or chlorine will totally kill the membranes..
So I'd not attempt a back flush with any water that was not first R/O and then ran through more carbon and stored. If I used it on a treated city water system . Besied whith any type or water source all you will be doing is just pushing more of what you think you are getting out by flushing it into membrane. I'd store mine in a refrigerator between uses and run them until plugged and then then toss them when full. But if it is set up and used daily with proper rejection amounts and carded for properly a membrane will last many yrs. I average 4 to 5 between filter and change my prefilter every 10 to 15,000 Gallons of water. And the .5 mic carbon block will also add lots of life to them ..

bouraganes · 01-19-2007, 09:52 AM

I'm a not so proud member of the never backflushed club- I think I had better take a look at it now!

Tangster · 01-19-2007, 09:59 AM

Quote:

Originally Posted by jtReef

Interesting Idea Tangster.
I will have to keep that in mind. I typically make RO water every other day and and in batches of 40gal. I also got my RO unit used from a friend so no directions. I had no idea this needed to be done.
So you telling me the best way to clean it is to turn the membrane around and flush it out right? The rest stays the same?

Its not an Idea its pure fact..

But I'd never use any R/O from an improperly stored and cared filter. It can make you very sick if not kill you.. Lost of nasties are trapped in the membrane just as they are supposed to be..Nitrates are in all water and are nitrites and ammonias and the cycle is just reversed .Plus anerobic and other bacterias. Who would use a old bandage back in the sore ?? To put it mildly .