Back Flushing Your RO/DI Unit-Filters, etc.. - Page 2-3reef Forums

jtReef · 01-19-2007, 10:53 AM

Very cool.
I appreciate the imput.
I guess I will just keep what i'm doing as it has been working.
I should probably replace the entire unit anyways.
Running about 400 gal in total with an RO unit that is only 30gpd so when i turn it on typically it goes for a full 24 hrs or like last week for the entire week :-)

Ill invest on the backflush kit this summer with a new unit for sure.

Tangster · 01-19-2007, 11:12 AM

I had a few guys to all of a sudden to get these alage bloom of green slime and red cyanos several yrs ago and I kept asking the questions and all had the same answers until I asked what was their rejection rate of waste .. Then they all went to they stored their units until needed . One even put his up in the attic crawl and one had his mounted right over the boiler (: and cut it on to fill his bucket as needed. Bingo! They both replaced their filters and then started to keep them cool and the problem wen away . best thing you could do is to just let it run about 10 maybe 15 gallons before you kept product water.. That way you will flush some of bacteria. I'd still keep the membrane in the old Fridge between uses it just takes a second to do. But thats just me..

grubbsj · 01-19-2007, 11:16 AM

I'm also a member of the 'don't backflush' club....

My RO unit is an older unit (10 years old) that is designed to make 5 gallons per day. It's out put, as measured over a 24 hour time run last week is 4.9 - 5 gallons. (The bucket is not marked any finner than that.) The TDS output (digital meter) is between 0 and 1. Then goes to my DI filter, which always has a 0 TDS out. Been

Not only have I not back flushed, I've never changed any of the 5 filters. Since there has not been any change in performance over the years, .... Well, if it is not broke, don't fix it.....

Joe

Tangster · 01-19-2007, 11:40 AM

Yes you make up water has a lot to do with it I'd look at a new carbon filter if you are on treated city water ? But a filter gets more efficient as it plugs up anyways and the D/I also helps you and 4 to 5 yrs I'd say was average if left in place and used often.
I have a friend in N.J on a 100 GPD he can get 3 maybe 4 gallons and the membrane is solid plugged up and fouled and thats running as much rejection and one can and still push a few drops past the membrane and a D.I refill will fill a bucket and its wasted.. I'm getting set up now to put a whole house in for him.. My son just set a 15,000 GPD units in a new Tobacco factory going up for their labs (: and all that water what is not used on its first trip down the closed loop recirculation system is r/o DI and used for the buildings toilets and or refiltered for the labs depending on the demand .

Blade_Runner · 01-20-2007, 08:54 PM

OK I backflush regularly. The instructions recommended backflushing every few months for 30 minutes. The directions stated that it would "greatly" extend the life of the filter. In this case I won't 2nd guess the manufacturer. I have regularly let it flush overnight. It runs my auto top off, so it is never off line. It is over 2 years old, has made thousands and thousands of gallons and still drops me from 3 to 400 ppm to 4-8. I really have a hard time believing that the RO is letting bacteria through. They are much larger than the filter.

Tangster · 01-21-2007, 05:27 AM

You Backwashing it with chlorinated water ? Ask and manufacture what chlorine will do to the membrane's ? And if the chlorine will not eat the film cells up ? As for trusting any manufacture LOL hum I wounder how long they want you filter to last 5 yrs or 1 yr maybe even months less then a full year. You really do not understand the mechanics of how the R/O works then .. Who made your membrane ? I mean really I don't care who does what I was just offering some information that I was supplied with by the manufacturer that I sold and installed their products for many yrs , but also it was potable water for Human consumption. don't take my word for it y'all do some research on this from someone not trying to sell you somthing..

ronmichel1115 · 01-21-2007, 05:36 AM

My Compact Reefer RO/DI unit instructions do not say anything about back flushing.

bouraganes · 01-21-2007, 06:01 AM

So Tangster - from what you are saying it is a real bad idea to use ro/di for a drinking water source in your home. I know several people that have been doing this for years- I wonder were they could get thier water tested for safety!

amcarrig · 01-21-2007, 07:11 AM

Quote:

Originally Posted by bouraganes

So Tangster - from what you are saying it is a real bad idea to use ro/di for a drinking water source in your home. I know several people that have been doing this for years- I wonder were they could get thier water tested for safety!

RO water is fine to drink. DI, is not.

I think that what Tangster is saying is that if you backflush your system using regular tap water, you will shorten the life of the membrane by exposing it to chlorinated water. Also, if the r.o. unit is not permenantly hooked up to a water source, all of the impurities, bacteria, etc., that are trapped in the membranes will multiply and all that crud will make it into the r.o.'s output. What we consider to be the "good" water would not be good at all.

Tangster · 01-21-2007, 08:01 AM

What I'm saying is R/O is fine to drink from a properly installed and maintained system. D/I last i read from some trade papers is that the studies had varying opinions and that was back in 2000 before I sold my business and got out of the trades. Its my sons problems now.. But if anyone thinks a R/O removes bacteria and minerals 100 percent re very m mistaken . And if you us a system that is plugged in and removed and allowed to set idle for a few weeks or days at Room temps then its your health as its full of all sorts of bacterias and all that have had dark moist anaerobic area to do their thing . And if you really understood the mechanicals of how they work then just using chlorinated or un filtered and clean water to flush them with you are first harming the TFC and only pushing more contaminates into the film. Unless something has changed and chlorine does not harm the films any longer ?

Think about the back flushing mechanics all you are doing is just using house pressure to run un treated or dechlorinated and mineral laden water over the film thats it..And as I said I'd find out if your unit can stand chlorine or minerals ? its best to use filtered R/O water to flush it with. There is nothing more I can add unless there have been some major changes in the construction and design of a R/O filter ? All I can add is ask some filtration people or experts and see what they have to say ? Or look up a article on the care and maintenance of a Potable R/O unit..