Does flushing membrane also flush TDS creep and carbon dust (RO/DI)

[Opus]

Yea I will change membrane every 12 to 18 months . My Water source TDS between 40 and 60.

If I had that kind of TDS to work with my membrane would last 15 years or more.

 

[Opus]

You don’t need a scientific study and there is no great flush kit sales conspiracy.

Waste gets trapped in the membrane pores, mostly in the form of scaling. Frequent flushes reduce this. A partially clogged membrane is less efficient than a clean membrane and TDS rejection and output rate decline as a result.

Many factors contribute to membrane life, not just the ‘TDS’ number of the input water. Your 400 TDS water and mine may be very different. If you really feel the need to dig in, GE has volumes of information on membrane design and data.

Don’t want to flush you membrane, by all means don’t.

I will not do it. I go by the old water guru that used to be on this board. He also said it didn't help much and he was in the water purification business.

 

[BeanAnimal]

I will not do it. I go by the old water guru that used to be on this board. He also said it didn't help much and he was in the water purification business.

You are talking about Russ - his advice on the matter was his opinion and contrary to the basic physics of the style of membrane we use in this hobby.... In the "purification business" or not.

I run 1:1 product to waste with 150-200 TDS that is somewhat hard and high in chloramines. My membrane is fast flushed (automated by a microcontroller) for ~15 seconds for every half our or so of operation. If I were to run this low of a rejection without the flush, my membrane would be destroyed in a matter of months.

Nobody is forcing you to flush your membrane. You indicated that you thought it (membrane flushing) was a scam based on hokum. It is not.

 

[Opus]

You are talking about Russ - his advice on the matter was his opinion and contrary to the basic physics of the style of membrane we use in this hobby.... In the "purification business" or not.

I run 1:1 product to waste with 150-200 TDS that is somewhat hard and high in chloramines. My membrane is fast flushed (automated by a microcontroller) for ~15 seconds for every half our or so of operation. If I were to run this low of a rejection without the flush, my membrane would be destroyed in a matter of months.

Nobody is forcing you to flush your membrane. You indicated that you thought it (membrane flushing) was a scam based on hokum. It is not.

I will go with his opinion over yours, and thankfully I live where I can have that choice of not doing something based on nothing.

 

[gbroadbridge]

Honestly up until the last membrane, I've never flushed my pre-filters and I've had a RO unit for 25+ years. I always get 5+ years out of my membranes so I have no idea how much longer flushing actually adds to the life of the membrane.

Mine was last replaced in 2015, and I only flush the input side of the membrane when I change the carbon filter.

 

[BeanAnimal]

I will go with his opinion over yours, and thankfully I live where I can have that choice of not doing something based on nothing.

Yes, you are free to ignore basic fact and go with whatever poorly formed opinion makes you happy. It by all means is your right.

 

[BeanAnimal]

Mine was last replaced in 2015, and I only flush the input side of the membrane when I change the carbon filter.

I think a lot of people skip (or do not understand the consequences) of skipping this step. The is enough dust in a new carbon block to fully (and permanently) foul a new membrane of the size that we use in the hobby.

 

[Opus]

Mine was last replaced in 2015, and I only flush the input side of the membrane when I change the carbon filter.

That is actually what I was trying to say. I had never flushed when changing the pre-filters.

 

[Opus]

Yes, you are free to ignore basic fact and go with whatever poorly formed opinion makes you happy. It by all means is your right.

Thinking about it, I have no idea who Russ is. That is not the person I was thinking of.

 

[BeanAnimal]

Thinking about it, I have no idea who Russ is. That is not the person I was thinking of.

That likely leaves Walter or AZ

I don't remember either of them advising that membrane flushing was useless (no care if they did). Nonetheless, it does not change the mechanics of how these membranes work.

 

[reefiniteasy]

To remove the TDS creep you need a DI bypass after the membrane, so you can flush the system and not send the initial high TDS water to your resin.

The red line in the picture is my bypass and the blue goes to the resin. I run the system for roughly 30 seconds bypassing the flow restrictor and DI resin. Then I close the waste line and transfer over to the resin line.

 

[thatmanMIKEson]

Lol our little tds inline testers are telling a quick head line to the story at best, if your relying on them as your sol indicator your already at a serious disadvantage, I can't believe a 60$ membrane is what puts some people on opposite sides of success. If you hold out for years just think about how long that is for the most important part of your reef tank, they run on water lol it seems important to me tds or not I'm changing and flushing it's super easy to do. It's funny to me the different perspectives of people, I don't think it's about the money, but for 60$ and piece of mind I change my filters and maintain them, just like everything else. Lol it's not a conspiracy!

 

[Randy Holmes-Farley]

I can't believe a 60$ membrane is what puts some people on opposite sides of success. If you hold out for years just think about how long that is for the most important part of your reef tank, they run on water lol it seems important to me tds or not I'm changing and flushing it's super easy to do. It's funny to me the different perspectives of people, I don't think it's about the money, but for 60$ and piece of mind I change my filters and maintain them, just like everything else. Lol it's not a conspiracy!

I’m not sure what problem I would be solving by flushing if the membrane lasted many years without it.

I don’t see any scenario where a clogged membrane lets through anything bad. What it would do is potentially waste water and time by reducing output.

 

[reefiniteasy]

I’m not sure what problem I would be solving by flushing if the membrane lasted many years without it.

I don’t see any scenario where a clogged membrane lets through anything bad. What it would do is potentially waste water and time by reducing output.

I do think a DI bypass is more important than the flush. I don’t know about others but I know my TDS at first turn on is ridiculously high. I would imagine my resin would be depleted much quicker if I didn’t flush the creep through the bypass.

 

[Miami Reef]

I ordered 100 GPD Reverse Osmosis Membrane - DOW Filmtec and Pre-Packed Bulk Deionization Resin (Color Changing)

Both from bulk reef supply. I hope hope hope I won’t have to deal with my membrane and DI not working after changing them again!

 

[thatmanMIKEson]

I’m not sure what problem I would be solving by flushing if the membrane lasted many years without it.

I don’t see any scenario where a clogged membrane lets through anything bad. What it would do is potentially waste water and time by reducing output.

I'm not sure either, usually when I'm not sure about something I trust the people that do, in this instance it's the manufacturers of the r.o membrane so I'm only going off their recommendations. It's easy enough for me to do, much easier than fighting a point I don't actually know. I don't see what the argument here is all about.

FilmTec™ Cleaning Procedures Technical Manual Excerpt - DuPont https://www.dupont.com/content/dam/...eaning-Procedures-Manual-Exc-45-D01696-en.pdf

 

[BeanAnimal]

Lol our little tds inline testers are telling a quick head line to the story at best, if your relying on them as your sol indicator your already at a serious disadvantage, I can't believe a 60$ membrane is what puts some people on opposite sides of success. If you hold out for years just think about how long that is for the most important part of your reef tank, they run on water lol it seems important to me tds or not I'm changing and flushing it's super easy to do. It's funny to me the different perspectives of people, I don't think it's about the money, but for 60$ and piece of mind I change my filters and maintain them, just like everything else. Lol it's not a conspiracy!

Not so sure that I agree that RODI is all that important. I ran without a properly functioning unit for the better part of 5 years. Roughly 150 tds right into tank daily on an ATO.

Of course source water maters and in some cases RO makes all the difference in the world.

 

[thatmanMIKEson]

Not so sure that I agree that RODI is all that important. I ran without a properly functioning unit for the better part of 5 years. Roughly 150 tds right into tank daily on an ATO.

Of course source water maters and in some cases RO makes all the difference in the world.

That's my world I guess, I can't/wont put my tap or under filtered water in my system, what others choose to do is fine by me, I just don't see the issue with covering all the bases.

That 150tds could be much different than my 4 tds and be a complete game changer after 5 years in a different size system, yours could be fine where mine hits a tipping point in year 2, these are all unknowns.

I think I will stick to my way, I have other things to worry about I take water quality off the list of possible issues now and in the future.

 

[BeanAnimal]

I am not (at all) advocating not using RODI. Just pointing out that it isn’t always the make or break thing.

 

[thatmanMIKEson]

I am not (at all) advocating not using RODI. Just pointing out that it isn’t always the make or break thing.

Of course not i agree!