GE R.O. Water Filter

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I installed 3 of the subject GE reverse osmosis water filters about a
year ago.  (The model number is PXRQ15RBL).  My daughter wanted one
(because she didn't like Los Angeles city water), so I stalled one at
her place.  I liked the way it installed easily, so when I returned to
my Ohio well water, I installed an identical model here.  Our well
water wasn't bad.  There was an occassional slight sulfer odor, but
testing indicated no harmful bacteria.  It is also softened.)  The
filter seemed to work well, but I found myself also drinking water
from a bar sink in the basement family room.  This seemed silly since
I had installed the filter upstairs - so I bought another filter and
installed it at the basement bar sink.  That's it for background - now
to my question:

The manual says to replace the "pre" and "post" filter canisters every
6 months.  To make the product seem high tech, they even provide a 6
month timer that lights an LED when the 6 months is up.  That is all
it is - a timer.  It does not measure usage, flow rate, or
contaminates at all.  So, how often do I really need to change the
canisters?  The filter installed upstairs is used for making coffee,
tea, and meals every day, while the filter at the bar sink is used for
only a few ounces of water no more often than once a week.

I can't imagine why both units need to have their filters changed at
the same time.  Do the filters get clogged?  (Mine haven't even on the
higher use sink).  Do the filters become contaminated with bacteria?
In that case, the lower use one might be worse.  (In my case, there
have been no foul odors nor reduced flow).  Both LED indicators went
on at 6 months and blinked until the batteries died.  I just can't see
spending $80 every 6 months for no reason.  Does anyone have any
inside information or real experience regarding these things?  How can
I tell when they really need to be changed?  Am I being reasonably
frugal or risking my life?

Pat

Re: GE R.O. Water Filter
Oops.  I meant this for alt.home.repair.  But, maybe someone here
knows.

Pat



Quoted text here. Click to load it

Re: GE R.O. Water Filter
Pat,

I worked in water purification for some time, the real way to test for a fi
lter that needs changing is the pressure drop over the unit. That applies t
o the RO unit as well as the prefilter. If you run the filter too long it w
ill rupture and the pressure drop will decrease drastically and all of the  
impurities will flow into your water.  

For the un-fun part the manufacturer would be the best person to tell you w
hat that pressure drop is to change the filter before you have a problem. I
n the home automation group I suspect the solution would be to track the pr
essure drop and have a light green as long as it's increasing and red when  
it decreases.  

For the most part you are safe because the contaminants are limited to the  
input side, any additional bacteria that grew would generally grow on the d
irty side of the filter. This will increase the pressure drop but not incre
ase your risk.

Re: GE R.O. Water Filter
Quoted text here. Click to load it

Some filters have a biocide in them (such as silver) to prevent bacterial
growth. This protection only has a limited life and may require the filter
to be changed for health reasons long before there's enough debris caught
to impact the flow rate.

Similarly, activated carbon filters will run out of pollutant absorbtion
capacity without actually blocking or impeding flow rate - they will
simply cease filtering out the pollutants, and in some cases could even
start releasing trapped pollutants back into the water flow.

--  
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Re: GE R.O. Water Filter
On Tuesday, December 16, 2014 11:55:02 AM UTC-5, Pat wrote:
Quoted text here. Click to load it

Pat,

I worked in water purification for some time, the real way to test for a fi
lter that needs changing is the pressure drop over the unit. That applies t
o the RO unit as well as the prefilter. If you run the filter too long it w
ill rupture and the pressure drop will decrease drastically and all of the  
impurities will flow into your water.  

For the un-fun part the manufacturer would be the best person to tell you w
hat that pressure drop is to change the filter before you have a problem. I
n the home automation group I suspect the solution would be to track the pr
essure drop and have a light green as long as it's increasing and red when  
it decreases.  

For the most part you are safe because the contaminants are limited to the  
input side, any additional bacteria that grew would generally grow on the d
irty side of the filter. This will increase the pressure drop but not incre
ase your risk.

Re: GE R.O. Water Filter
wrote:

Quoted text here. Click to load it

Keith,
Thanks for the information.  That is just what I was looking for. Over
on alt.home.repair, someone found that the filters are designed for
900 gallons of use.  That would mean about 2-1/2 years on my one unit
and 75 years on the other.  I decided to change them both every two
years or so.

Pat

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