RO unit component replacement?

[Richard Periut]

Hi all,

I have a GE RO unit, which is close to two years old.

Last year, I replaced the pre and post filters.

Now, about almost a year after that, I've noticed that instead of doing
two and a half gallons at a time, (coming from the storage tank,) it's
only doing about 1 and 1/2 gallons at a time.

As per my conductivity meter, the readings for the output are still the
same as when I installed the system two years ago.

My question: should I just replace the pre and post again, or is this
reduction in production a sign of a failing membrane, and it would be
prudent to replace all three components?

Its capacity is 2.5 gallons per hour, and I only use about 3 gallons per
day.

TIA,

Richard




















--
"..A census taker once tried to test me. I ate his liver with some fava
beans and a nice chianti..."

Hannibal "The Cannibal"

Silence Of The Lambs 1991

[Marc Levenson]

Richard, there are a couple of things to consider:

PSI - has it changed?
Temp - when water is colder, the flow is reduced and it takes longer to make the
same amount of water.
Sediment Filter - 5 micron is normal for most units, but I've seen people
purchase 0.5 micron hoping to pull out even more impurities. The problem is
that .5 will clog much faster and make it harder for water to penetrate at the
same rate as before. Solution is to change the filter more often, or use a 5
micron filter.

Your RO membrane should be good for a few more years, unless you have really
high TDS source water.

Marc


Richard Periut wrote:

> Hi all,
>
> I have a GE RO unit, which is close to two years old.
>
> Last year, I replaced the pre and post filters.
>
> Now, about almost a year after that, I've noticed that instead of doing
> two and a half gallons at a time, (coming from the storage tank,) it's
> only doing about 1 and 1/2 gallons at a time.
>
> As per my conductivity meter, the readings for the output are still the
> same as when I installed the system two years ago.
>
> My question: should I just replace the pre and post again, or is this
> reduction in production a sign of a failing membrane, and it would be
> prudent to replace all three components?
>
> Its capacity is 2.5 gallons per hour, and I only use about 3 gallons per
> day.
>
> TIA,
>
> Richard
>
> --
> "..A census taker once tried to test me. I ate his liver with some fava
> beans and a nice chianti..."
>
> Hannibal "The Cannibal"
>
> Silence Of The Lambs 1991

--
Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com

[Richard Periut]

Marc Levenson wrote:
> Richard, there are a couple of things to consider:
>
> PSI - has it changed?
> Temp - when water is colder, the flow is reduced and it takes longer to make the
> same amount of water.
> Sediment Filter - 5 micron is normal for most units, but I've seen people
> purchase 0.5 micron hoping to pull out even more impurities. The problem is
> that .5 will clog much faster and make it harder for water to penetrate at the
> same rate as before. Solution is to change the filter more often, or use a 5
> micron filter.
>
> Your RO membrane should be good for a few more years, unless you have really
> high TDS source water.
>
> Marc
>
>


Hi Marc, and thanks for the response.

I don't think it's the Temp, mainly because when I replaced the filter
last year, it was very cold, and the water flow was as normal. Now the
size of the filter could be the issue. I don't know what it is, only
that it was a replacement that I purchased at Costco.

I was just worried about the membrane. When do I know it's starting to
fail, when my conductivity meter shows that the membrane is allowing
more than 10 % of compounds to get in?

Currently my tap reads 550 microsiemens, and the output of the RO unit
reads 15. That's been the case throughout the life of the unit, with
very little fluctuation.

TIA,

Richard

--
"..A census taker once tried to test me. I ate his liver with some fava
beans and a nice chianti..."

Hannibal "The Cannibal"

Silence Of The Lambs 1991

[Marc Levenson]

I would guess it is your filter cartridges. I know that Costco and Home Depot/Lowes
carry various types, but I don't know their micron values.

I'll have to find out how to know when a RO membrane is exhausted.

Marc


Richard Periut wrote:

> I don't think it's the Temp, mainly because when I replaced the filter
> last year, it was very cold, and the water flow was as normal. Now the
> size of the filter could be the issue. I don't know what it is, only
> that it was a replacement that I purchased at Costco.
>
> I was just worried about the membrane. When do I know it's starting to
> fail, when my conductivity meter shows that the membrane is allowing
> more than 10 % of compounds to get in?
>
> Currently my tap reads 550 microsiemens, and the output of the RO unit
> reads 15. That's been the case throughout the life of the unit, with
> very little fluctuation.
>
> TIA,
>
> Richard
>

--
Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com

[CapFusion]

"Marc Levenson" > wrote in message
...
> I would guess it is your filter cartridges. I know that Costco and Home
Depot/Lowes
> carry various types, but I don't know their micron values.
>
> I'll have to find out how to know when a RO membrane is exhausted.
>
> Marc
I would say or guess your membrane is wearing out / clog abit. It also
depend on how much ppm you want for your output / result of your RO.
Try testing RO again without your membrane and see how much ppm you get.
In-another-word, testing each stage and see how much performance you get
from it.
Example:
1. Pre-filter (sediment) + first carbon block
2. Pre-filter (sediment) + first carbon block + 2nd carbon block
3. Pre-filter (sediment) + 2nd carbon block
4. Pre-filter (sediment) + first carbon block + membrane

Any stage that is not up to efficiency, you may need to replace that stage.
Again, depending on how much purities you want. I normally check when my
result output indicate 5ppm (TDS), Someone may want to let it go until about
10 or 15ppm before changing.

When to change the membrance depend on how hardness from your water source.
Check your RO gauge also. The lower the PSI, the performance will be less as
PSI get lower.

Maybe this link from someone before post regarding about RO/DI will give you
a general idea.
http://www.netpets.org/fish/reference/srab/srab4.html

CapFusion,...

[Richard Periut]

CapFusion wrote:
> "Marc Levenson" > wrote in message
> ...
>
>>I would guess it is your filter cartridges. I know that Costco and Home
>
> Depot/Lowes
>
>>carry various types, but I don't know their micron values.
>>
>>I'll have to find out how to know when a RO membrane is exhausted.
>>
>>Marc
>
> I would say or guess your membrane is wearing out / clog abit. It also
> depend on how much ppm you want for your output / result of your RO.
> Try testing RO again without your membrane and see how much ppm you get.
> In-another-word, testing each stage and see how much performance you get
> from it.
> Example:
> 1. Pre-filter (sediment) + first carbon block
> 2. Pre-filter (sediment) + first carbon block + 2nd carbon block
> 3. Pre-filter (sediment) + 2nd carbon block
> 4. Pre-filter (sediment) + first carbon block + membrane
>
> Any stage that is not up to efficiency, you may need to replace that stage.
> Again, depending on how much purities you want. I normally check when my
> result output indicate 5ppm (TDS), Someone may want to let it go until about
> 10 or 15ppm before changing.
>
> When to change the membrance depend on how hardness from your water source.
> Check your RO gauge also. The lower the PSI, the performance will be less as
> PSI get lower.
>
> Maybe this link from someone before post regarding about RO/DI will give you
> a general idea.
> http://www.netpets.org/fish/reference/srab/srab4.html
>
> CapFusion,...
>
>

High CapFusion,

Thanks for the response. I only have a 3 stage system: prefilter /
membrane / postfilter.

I don't test for TDS, but rather, test for conductivity with my
conductivity meter. The tap water reads 500+, and the water post filter
reads about 15. This has been the case throughout the life of the
filter, even last year when I changed the pre and post.

I assume that when the membrane starts to fail, the conductivity of the
post water will start to rise. My question is, when a membrane fails, is
this a gradual phenomenon, or is it an acute process?

TIA,

Richard

--
"..A census taker once tried to test me. I ate his liver with some fava
beans and a nice chianti..."

Hannibal "The Cannibal"

Silence Of The Lambs 1991

[CapFusion]

In any stage(s), it should be gradual clog (or fail) until some will
eventually go through it. By this time, you should need to change it. When
it sudden (acute), your flow should be rapid (no restriction) from output
since it damage already. The only time I can think of when it suddenly get
clog is when the "Water Department" doing some work (construction) on the
main pipe. You will need to flush your incoming sud before you reattach your
RO if this occur.

Again, depending on how pure your output you want, this is the indication
you will need to change your cartridge. TDS and PSI RO gauge are good
indication of your RO performance duty.

OT Suggestion:
Better if you can add another or two to after your pre-filter before your
membrane. It will make your membrane last a bit longer. Or just another
pre-filter and one block. This will save you few buck in long term. Reason,
prefilter and carbon block is cheaper to change when compare to membrane,
especially if your area are on the heavy side.

Pre-filter (sediment) - cheap - ~$5.99 (1 micron)
Carbon block - Ok ~ $9.99 (1 micron)
Membrane - Expensive ~$49.99 (100GPD)

CapFusion,...



> High CapFusion,
>
> Thanks for the response. I only have a 3 stage system: prefilter /
> membrane / postfilter.
>
> I don't test for TDS, but rather, test for conductivity with my
> conductivity meter. The tap water reads 500+, and the water post filter
> reads about 15. This has been the case throughout the life of the
> filter, even last year when I changed the pre and post.
>
> I assume that when the membrane starts to fail, the conductivity of the
> post water will start to rise. My question is, when a membrane fails, is
> this a gradual phenomenon, or is it an acute process?
>
> TIA,
>
> Richard
>
> --
> "..A census taker once tried to test me. I ate his liver with some fava
> beans and a nice chianti..."
>
> Hannibal "The Cannibal"
>
> Silence Of The Lambs 1991
>

[Richard Periut]

CapFusion wrote:
> In any stage(s), it should be gradual clog (or fail) until some will
> eventually go through it. By this time, you should need to change it. When
> it sudden (acute), your flow should be rapid (no restriction) from output
> since it damage already. The only time I can think of when it suddenly get
> clog is when the "Water Department" doing some work (construction) on the
> main pipe. You will need to flush your incoming sud before you reattach your
> RO if this occur.
>
> Again, depending on how pure your output you want, this is the indication
> you will need to change your cartridge. TDS and PSI RO gauge are good
> indication of your RO performance duty.
>
> OT Suggestion:
> Better if you can add another or two to after your pre-filter before your
> membrane. It will make your membrane last a bit longer. Or just another
> pre-filter and one block. This will save you few buck in long term. Reason,
> prefilter and carbon block is cheaper to change when compare to membrane,
> especially if your area are on the heavy side.
>
> Pre-filter (sediment) - cheap - ~$5.99 (1 micron)
> Carbon block - Ok ~ $9.99 (1 micron)
> Membrane - Expensive ~$49.99 (100GPD)
>
> CapFusion,...
>
>
>
>
>>High CapFusion,
>>
>>Thanks for the response. I only have a 3 stage system: prefilter /
>>membrane / postfilter.
>>
>>I don't test for TDS, but rather, test for conductivity with my
>>conductivity meter. The tap water reads 500+, and the water post filter
>>reads about 15. This has been the case throughout the life of the
>>filter, even last year when I changed the pre and post.
>>
>>I assume that when the membrane starts to fail, the conductivity of the
>>post water will start to rise. My question is, when a membrane fails, is
>>this a gradual phenomenon, or is it an acute process?
>>
>>TIA,
>>
>>Richard
>>
>>--
>>"..A census taker once tried to test me. I ate his liver with some fava
>>beans and a nice chianti..."
>>
>>Hannibal "The Cannibal"
>>
>>Silence Of The Lambs 1991
>>
>
>
>

Thanks for your advice.

Richard


--
"..A census taker once tried to test me. I ate his liver with some fava
beans and a nice chianti..."

Hannibal "The Cannibal"

Silence Of The Lambs 1991

[Bill Kirkpatrick]

Step 1.

If you don't already have a bypass flush valve on the unit,
then remove the flow rate limiter from the waste drain and
set the unit to produce water.

Let water blow through the membrane to waste, unlimited,
until the waste water runs clear, or 2 minutes, whichever is
longer. A white 5G bucket is nice.

Membranes can fail "open", if membrane is TFC and eaten away
by Chlorine, or "clogged" with time. Your meter is your
definitive guide for the "open" condition. Bad water, bad
membrane.

Step 2.

Verify your supply pressure and temp. haven't changed
substantially. ROs make less water with low pressure, or
when water is warm.

Step 3.

Pre-filter clogging will reduce output (by reducing
pressure). Some carbon blocks have remarkably small micron
ratings, .5 or so. These can clog very quickly if proper
sediment pre-filters aren't used. To diagnose this, remove
the feed line into the membrane (supply valve off, first!)
and measure the output from the pre-filters into a bucket.
If your pre-filters are putting out at 6 times your GPD
rating, or more - your membrane is likely clogged.
(Remember, flush early, flush often, and always before you
declare a membrane dead by clogging.)

Oh, you didn't install one of those ceramic cartridges as
pre-filter, did you? These can lower flow/pressure to the
membrane dramatically.

Step 3 (optional, just a good idea).

Install a couple 'o Ts and a valve to bypass waste flow
around your flow limiter. Open the value to flush the
membrane (when the RO is in production mode) for 1-2 minutes
once a week or so.

You need 2-T's, and 1 valve. John Guest fittings make this
a 2 minute surgery. Cut the lines into and out of the flow
limiter, install long end of the Ts. Add 2 short lengths of
tube, with the valve in the middle, into the short lengths
of the T. Done. Open valve to flush.

Oh, you may have a not-so-atypical design that has its flow
limiter bundled into the membrane cartridge. A sorry
marketing trick geared to maximize replacement membrane
sales by minimizing customer flushing. (My Kent Maxxima came
that way) But, just order a proper limiter from the web, rip
out the old one, and fix the problem.


*****************************
Richard Periut wrote:
>
> My question: should I just replace the pre and post again, or is this
> reduction in production a sign of a failing membrane, and it would be
> prudent to replace all three components?>
>
>
>
>
>
>
>
>
>
>
>
>
>
>