pH/ORP meter maintenance

"Boomer" <wcwing_nospam_@chartermi.net> wrote in message news:...
> There are a number of different types of pH probes, more or less you get what you pay for.
> The two most basic are Double Junction and Single Junction. Some probes are refillable,
> others are not.

Do you keep the filling hole open when measuring with a refillable electrode?
Can you make filling solution home or does it require laboratory environment
to refill such electrode?

> No, you don't want the stuff leaking in your tank, that probe sounds like
> it is not sealed right. The salt is KCl and silver chloride leaking out do to salt creep,
> just like the salt creep you often see on hoses, filters or on the glass hinge.

I see it has a filling hole in the upper part, but the salt creep is on the
bottom glass bulb. Like it escaped throught the glass... Is it posiible or not?
About 1cm higher from the bulb there is a rubber/silicone ring around the probe
and above it there is only glass to the top with a filling hole covered with
another, this time transparrent, rubber/silicone ring. The salt deposits are
around bulb and little around lower rubber band... Do you think it is leaking??
Would you try to revive this dried electrode or is it junk now, after 6 month
of dry storage? I do not see the decrease of the internal fluid amount, so
the leakage, if exists, is microscopic only causing salt deposits on the bulb.

> It should be OK, if it is calibrated correctly, it should be Calibrated to pH 7 and Sloped
> to pH 9
> ***NOT pH 7 & pH 4. This will make the probe less accurate, as the slope is in the wrong
> direction 7 ---> 4 and it should be 7--->9 .
>
> What are the calibration solution pH's

pH 9? That is strange - from what I see around, they offer buffers in three
values commonly: 4.01, 7, 10.01 - never seen one for pH 9. Where can I buy one?

> "From what I remember from school, digital meters accuracy
> is always decreased of the value of the last digit, so in this
> case best accuracy would be 0.01 +/- 0.01"
>
> Yes, + or - 0.01

So it makes maximal acuracy of the whole measurement no better than 0.02 pH.
What will be the effect of the quality of buffers used for the calibration?
I remember learning about calibration, it should be at least one raw of acuracy
better than the measurment cunducted, so to calibrate meter for 0.01 acuracy
measurements you need to use buffers more acurate than that...

> Probes should be cleaned and calibrated every week, to insure accuracy

Thanks.

> Yes, in time it will drift and it will become harder to calibrate.The best
> indication is the longer time it takes for the meter value to become stable.

What is the typical time it should become stable? Long/short is quite relative...
Is 2-3 minutes good response time or is it too slow already?

> Go year and register
>
> http://www.radiometer-analytical.com...?code=112&s=go
>
> Download pH Theory and Application
>
> also
>
> http://www.coleparmer.com/techinfo/t...pH+Measurement
>
> and
>
> http://www.sensorex.com/support/supp..._articles.html

Thanks Boomer - I will read this articles soon )

> We just started to work on an article Randy will be writing in a 2 part series.One
> on pH meters and one on pH indicators/test kits. This will explain it all shortly

Where/when do yoy plan to publish this article?

See below

--
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If You See Me Running You Better Catch-Up
"Pszemol" <> wrote in message news:...
: "Boomer" <wcwing_nospam_@chartermi.net> wrote in message
news:...
: > There are a number of different types of pH probes, more or less you get what you pay
for.
: > The two most basic are Double Junction and Single Junction. Some probes are
refillable,
: > others are not.
:
: Do you keep the filling hole open when measuring with a refillable electrode?

OPEN, NEVER SEAL IT SHUT, AS THE SOLUTION WILL NOT BE ABLE TO FLOW RIGHT THROUGH THE REF.
JUNCITON

: Can you make filling solution home or does it require laboratory environment
: to refill such electrode?
:
: > No, you don't want the stuff leaking in your tank, that probe sounds like
: > it is not sealed right. The salt is KCl and silver chloride leaking out do to salt
creep,
: > just like the salt creep you often see on hoses, filters or on the glass hinge.
:
: I see it has a filling hole in the upper part, but the salt creep is on the


OK, THAT IS NORMAL AT TIMES AFTER STORAGE, RINSE THE PROBE AND BLOT DRY ANMD THEN TRY TO
CALIBRATE IT


: bottom glass bulb. Like it escaped throught the glass... Is it posiible or not?

NO, IT IS ESCAPING THROUGH THE REF JUNTION WHICH IS NORMAL, IN THIE CASE. IT LEAKS THROUGH
THE ANNULAR REF. JUNCTION


: About 1cm higher from the bulb there is a rubber/silicone ring around the probe
: and above it there is only glass to the top with a filling hole covered with
: another, this time transparrent, rubber/silicone ring. The salt deposits are
: around bulb and little around lower rubber band...

YES, THE ANNULAR REF JUINCTION DON'T WORRY

Do you think it is leaking??
: Would you try to revive this dried electrode or is it junk now, after 6 month
: of dry storage? I do not see the decrease of the internal fluid amount, so

OK, THAT IS GOOD IT THE LEVEL IS UP TO THE FILL HOLE

THE PROBE SHOUOLD NEVER BE STORED DRY. THE PROBE SHOULD NEVER BE STORED IN DI OR RO WATER,
THE THE PROBE WILL BECOME USLESS. BUT A 4 M KCl SOLUTION OR AT LEAST pH 4 BUFFER (SUCH HAS
THAT USED FOR CALIBRATION)


: the leakage, if exists, is microscopic only causing salt deposits on the bulb.
:
: > It should be OK, if it is calibrated correctly, it should be Calibrated to pH 7 and
Sloped
: > to pH 9
: > ***NOT pH 7 & pH 4. This will make the probe less accurate, as the slope is in the
wrong
: > direction 7 ---> 4 and it should be 7--->9 .
: >
: > What are the calibration solution pH's
:
: pH 9? That is strange - from what I see around, they offer buffers in three
: values commonly: 4.01, 7, 10.01 - never seen one for pH 9. Where can I buy one?

THEY ARE QUITE COMMON

READ THIS

http://www.austral.addr.com/process_monitoring/pH2.htm

pH 9 BUFFER CALIBRATION SOLUTIONS WEBSITES

http://www.spectronic.co.uk/buffers.htm

http://www.rmsupply.co.uk/sentek_sup...hensive_ra.htm

I LIKE THESE

http://www.vitrum.cz/snail/eng/pufry.htm


:
: > "From what I remember from school, digital meters accuracy
: > is always decreased of the value of the last digit, so in this
: > case best accuracy would be 0.01 +/- 0.01"
: >
: > Yes, + or - 0.01
:
: So it makes maximal acuracy of the whole measurement no better than 0.02 pH.

IT MEANS IF THE pH IS 8.00 IT MAY BE ANYWHERE FROM 7.99-8.01


: What will be the effect of the quality of buffers used for the calibration?

NOT MUCH FOR REEF KEEPING. N.I.S.T. BUFERS ARE THE BEST BUT COST MORE


: I remember learning about calibration, it should be at least one raw of acuracy
: better than the measurment cunducted, so to calibrate meter for 0.01 acuracy
: measurements you need to use buffers more acurate than that...
:
: > Probes should be cleaned and calibrated every week, to insure accuracy
:
: Thanks.
:
: > Yes, in time it will drift and it will become harder to calibrate.The best
: > indication is the longer time it takes for the meter value to become stable.
:
: What is the typical time it should become stable? Long/short is quite relative...
: Is 2-3 minutes good response time or is it too slow already?


NO, IT SHOULD BE IN SEOCNDS MIN IS WAY TO LONG
:
: > Go year and register
: >
: > http://www.radiometer-analytical.com...?code=112&s=go
: >
: > Download pH Theory and Application
: >
: > also
: >
: >
http://www.coleparmer.com/techinfo/t...aq%2Eht m&Tit
le=pH+Measurement
: >
: > and
: >
: > http://www.sensorex.com/support/supp..._articles.html
:
: Thanks Boomer - I will read this articles soon )
:
: > We just started to work on an article Randy will be writing in a 2 part series.One
: > on pH meters and one on pH indicators/test kits. This will explain it all shortly
:
: Where/when do yoy plan to publish this article?

THEY WILL APPEAR IN ONE OF THESE TWO ON-LINE MAGAZINES

http://www.advancedaquarist.com/index.htm

http://reefkeeping.com/index.htm

TWO MORE ARE WORKING ON ARE ORP AND CHLORAMINE CHEMISTRY, TO COME OUT SOON

TO SEE MOST OF THE ARTICLES ALREADY OUT GO HERE

http://reefcentral.com/forums/showth...hreadid=102605

HAVE YOU NEVER SEEN THIS AT THE BOTTOM OF ALL MY POSTS

Want to talk chemistry ? The Reef Chemistry Forum
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Thanks Boomer for all the info.
With all this links I will have long reading before I go to sleep tonight
Thank you again.

In article <>, Pszemol <> wrote:
>Boomer, do you know of any difference in pH probes dedicated
>to long-term monitoring or to take lab sample measurments?
>Are these the same probes or do they differ in design?

Some of the electrodes for long-run applications have a slow
continuous flow of KCl through them. That isn't desirable or
even necessary for aquarium purposes.

You get about six good months out of most non-refillable electrodes
in an aquarium setting. After that, they become increasingly
flakey as the internal elecrolyte gets weaker.

pH electrodes tend to last longer in saltwater tanks than in
freshwater tanks, in my experience.

>I am concerned in two issues here: acuracy of prolonged test
>disturbed by the long time between calibrations and the
>filling solution leaking to the fish tank when the total
>water amount is relatively small, lets say nano-reef...
>I have purchased two pH glass electrodes in April this year
>and one of them was not used, in the box. When I open it
>yesterday I noticed a large amount of white salt on the
>probe junction bulb indicating the probe absorbed something
>from the air OR it leaked filling solution which dried out
>causing salt deposits on the electrode glass...

Yeah, the solution that leaked out is 4M KCl. It is normal
to find some crust around the packing when you get a new
electrode.

>If the second is true explanation, how does this leaking process
>affect our tank chemistry? Should we be concerns in "small"
>amounts of Silver ions (Ag) leaking to the water?

Very little silver comes out of an electrode in normal operation,
and Ag+ is rock insoluble in salt water. It isn't a significant
concern.

>BTW - do you know if anybody verified acuracy of the Pinpoint
>meter to confirm what manufacturer states is true? Aside from
>the meter acuracy, is it possible to measure pH with this
>meter/electrode with acuracy of 0.01 in a regular reef tank?
>From what I remember from school, digital meters acuracy
>is always decreased of the value of the last digit, so in this
>case best acuracy would be 0.01 +/- 0.01, number larger than 0.01
>Acuracy received after long periods from last calibration would
>be probably much worse than that... What is your opinion about it?

Many years ago, I did a test of a (one copy) of a pinpoint meter
compared to a reference quality meter in lab. It was within 0.02
or 0.03 from the reference setup. This was with a fresh electrode.
Old electrodes get quite freaky after many months in the system, and
aren't to be trusted.

Craig Bingman

--
--

Craig, I didn't know you read this NG!
Anyway I get about 5 to 8 months use out of my Ph probe before it does not
calibrate. You would think it should be more consistent & that around the
same time frame they would just not calibrate. I think a 90 day window on
when it goes bad might be a QC issue. It's still a great way to be able to
check your Ph with ease whenever you are by the tank.
Steve

"Craig Bingman" <> wrote in message
news:bp1s41$9he$...
> In article <>, Pszemol <>
wrote:
> >Boomer, do you know of any difference in pH probes dedicated
> >to long-term monitoring or to take lab sample measurments?
> >Are these the same probes or do they differ in design?
>
> Some of the electrodes for long-run applications have a slow
> continuous flow of KCl through them. That isn't desirable or
> even necessary for aquarium purposes.
>
> You get about six good months out of most non-refillable electrodes
> in an aquarium setting. After that, they become increasingly
> flakey as the internal elecrolyte gets weaker.
>
> pH electrodes tend to last longer in saltwater tanks than in
> freshwater tanks, in my experience.
>
> >I am concerned in two issues here: acuracy of prolonged test
> >disturbed by the long time between calibrations and the
> >filling solution leaking to the fish tank when the total
> >water amount is relatively small, lets say nano-reef...
> >I have purchased two pH glass electrodes in April this year
> >and one of them was not used, in the box. When I open it
> >yesterday I noticed a large amount of white salt on the
> >probe junction bulb indicating the probe absorbed something
> >from the air OR it leaked filling solution which dried out
> >causing salt deposits on the electrode glass...
>
> Yeah, the solution that leaked out is 4M KCl. It is normal
> to find some crust around the packing when you get a new
> electrode.
>
> >If the second is true explanation, how does this leaking process
> >affect our tank chemistry? Should we be concerns in "small"
> >amounts of Silver ions (Ag) leaking to the water?
>
> Very little silver comes out of an electrode in normal operation,
> and Ag+ is rock insoluble in salt water. It isn't a significant
> concern.
>
> >BTW - do you know if anybody verified acuracy of the Pinpoint
> >meter to confirm what manufacturer states is true? Aside from
> >the meter acuracy, is it possible to measure pH with this
> >meter/electrode with acuracy of 0.01 in a regular reef tank?
> >From what I remember from school, digital meters acuracy
> >is always decreased of the value of the last digit, so in this
> >case best acuracy would be 0.01 +/- 0.01, number larger than 0.01
> >Acuracy received after long periods from last calibration would
> >be probably much worse than that... What is your opinion about it?
>
> Many years ago, I did a test of a (one copy) of a pinpoint meter
> compared to a reference quality meter in lab. It was within 0.02
> or 0.03 from the reference setup. This was with a fresh electrode.
> Old electrodes get quite freaky after many months in the system, and
> aren't to be trusted.
>
> Craig Bingman
>
> --
> --
>
>

Craig

Nice to see you back, been a long time

--
Boomer

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If You See Me Running You Better Catch-Up
"Craig Bingman" <> wrote in message
news:bp1s41$9he$...
: In article <>, Pszemol <> wrote:
: >Boomer, do you know of any difference in pH probes dedicated
: >to long-term monitoring or to take lab sample measurments?
: >Are these the same probes or do they differ in design?
:
: Some of the electrodes for long-run applications have a slow
: continuous flow of KCl through them. That isn't desirable or
: even necessary for aquarium purposes.
:
: You get about six good months out of most non-refillable electrodes
: in an aquarium setting. After that, they become increasingly
: flakey as the internal elecrolyte gets weaker.
:
: pH electrodes tend to last longer in saltwater tanks than in
: freshwater tanks, in my experience.
:
: >I am concerned in two issues here: acuracy of prolonged test
: >disturbed by the long time between calibrations and the
: >filling solution leaking to the fish tank when the total
: >water amount is relatively small, lets say nano-reef...
: >I have purchased two pH glass electrodes in April this year
: >and one of them was not used, in the box. When I open it
: >yesterday I noticed a large amount of white salt on the
: >probe junction bulb indicating the probe absorbed something
: >from the air OR it leaked filling solution which dried out
: >causing salt deposits on the electrode glass...
:
: Yeah, the solution that leaked out is 4M KCl. It is normal
: to find some crust around the packing when you get a new
: electrode.
:
: >If the second is true explanation, how does this leaking process
: >affect our tank chemistry? Should we be concerns in "small"
: >amounts of Silver ions (Ag) leaking to the water?
:
: Very little silver comes out of an electrode in normal operation,
: and Ag+ is rock insoluble in salt water. It isn't a significant
: concern.
:
: >BTW - do you know if anybody verified acuracy of the Pinpoint
: >meter to confirm what manufacturer states is true? Aside from
: >the meter acuracy, is it possible to measure pH with this
: >meter/electrode with acuracy of 0.01 in a regular reef tank?
: >From what I remember from school, digital meters acuracy
: >is always decreased of the value of the last digit, so in this
: >case best acuracy would be 0.01 +/- 0.01, number larger than 0.01
: >Acuracy received after long periods from last calibration would
: >be probably much worse than that... What is your opinion about it?
:
: Many years ago, I did a test of a (one copy) of a pinpoint meter
: compared to a reference quality meter in lab. It was within 0.02
: or 0.03 from the reference setup. This was with a fresh electrode.
: Old electrodes get quite freaky after many months in the system, and
: aren't to be trusted.
:
: Craig Bingman
:
: --
: --
:
:

"Craig, I didn't know you read this NG!"

He has been here for over a decade, do a search on him. He has been gone for a year or so,
his new job has kept him pretty busy


--
Boomer

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If You See Me Running You Better Catch-Up
"Steve "Srfmon"" <surferstevo@"nospam"socal.rr.com> wrote in message
news:iO_sb.22092$...
: Craig, I didn't know you read this NG!
: Anyway I get about 5 to 8 months use out of my Ph probe before it does not
: calibrate. You would think it should be more consistent & that around the
: same time frame they would just not calibrate. I think a 90 day window on
: when it goes bad might be a QC issue. It's still a great way to be able to
: check your Ph with ease whenever you are by the tank.
: Steve
:
: "Craig Bingman" <> wrote in message
: news:bp1s41$9he$...
: > In article <>, Pszemol <>
: wrote:
: > >Boomer, do you know of any difference in pH probes dedicated
: > >to long-term monitoring or to take lab sample measurments?
: > >Are these the same probes or do they differ in design?
: >
: > Some of the electrodes for long-run applications have a slow
: > continuous flow of KCl through them. That isn't desirable or
: > even necessary for aquarium purposes.
: >
: > You get about six good months out of most non-refillable electrodes
: > in an aquarium setting. After that, they become increasingly
: > flakey as the internal elecrolyte gets weaker.
: >
: > pH electrodes tend to last longer in saltwater tanks than in
: > freshwater tanks, in my experience.
: >
: > >I am concerned in two issues here: acuracy of prolonged test
: > >disturbed by the long time between calibrations and the
: > >filling solution leaking to the fish tank when the total
: > >water amount is relatively small, lets say nano-reef...
: > >I have purchased two pH glass electrodes in April this year
: > >and one of them was not used, in the box. When I open it
: > >yesterday I noticed a large amount of white salt on the
: > >probe junction bulb indicating the probe absorbed something
: > >from the air OR it leaked filling solution which dried out
: > >causing salt deposits on the electrode glass...
: >
: > Yeah, the solution that leaked out is 4M KCl. It is normal
: > to find some crust around the packing when you get a new
: > electrode.
: >
: > >If the second is true explanation, how does this leaking process
: > >affect our tank chemistry? Should we be concerns in "small"
: > >amounts of Silver ions (Ag) leaking to the water?
: >
: > Very little silver comes out of an electrode in normal operation,
: > and Ag+ is rock insoluble in salt water. It isn't a significant
: > concern.
: >
: > >BTW - do you know if anybody verified acuracy of the Pinpoint
: > >meter to confirm what manufacturer states is true? Aside from
: > >the meter acuracy, is it possible to measure pH with this
: > >meter/electrode with acuracy of 0.01 in a regular reef tank?
: > >From what I remember from school, digital meters acuracy
: > >is always decreased of the value of the last digit, so in this
: > >case best acuracy would be 0.01 +/- 0.01, number larger than 0.01
: > >Acuracy received after long periods from last calibration would
: > >be probably much worse than that... What is your opinion about it?
: >
: > Many years ago, I did a test of a (one copy) of a pinpoint meter
: > compared to a reference quality meter in lab. It was within 0.02
: > or 0.03 from the reference setup. This was with a fresh electrode.
: > Old electrodes get quite freaky after many months in the system, and
: > aren't to be trusted.
: >
: > Craig Bingman
: >
: > --
: > --
: >
: >
:
:

"Craig Bingman" <> wrote in message news:bp1s41$9he$...
> Some of the electrodes for long-run applications have a slow
> continuous flow of KCl through them. That isn't desirable or
> even necessary for aquarium purposes.
>
> You get about six good months out of most non-refillable electrodes
> in an aquarium setting. After that, they become increasingly
> flakey as the internal elecrolyte gets weaker.
>
> pH electrodes tend to last longer in saltwater tanks than in
> freshwater tanks, in my experience.

So if I understand correctly, the main reason the electrode goes bad
is the process of leaking fresh water to the inside of the probe and
dissolving filling solution (osmosis)? In this case, if I buy refilable
electrode and a bottle of 4M KCL I can revive the electrode every month?

> Yeah, the solution that leaked out is 4M KCl. It is normal
> to find some crust around the packing when you get a new
> electrode.

Thanks.

> Very little silver comes out of an electrode in normal operation,
> and Ag+ is rock insoluble in salt water. It isn't a significant
> concern.

Understand. What do they exactly mean when they state "the filling
solution is 4M KCL saturated with AgCl" - is AgCl dissolved in the
filling solution or rather the filling solution is pure KCl and
Ag comes from the silver wire inside the electrode?

> Many years ago, I did a test of a (one copy) of a pinpoint meter
> compared to a reference quality meter in lab. It was within 0.02
> or 0.03 from the reference setup. This was with a fresh electrode.
> Old electrodes get quite freaky after many months in the system, and
> aren't to be trusted.

So the real acuracy of Pinpoint meter with electrode is 0.02
decreased with regular (+/-)0.01 which comes from digital reading.
Have you tested other meters claiming 0.01 acuracy? What about Milwaukee?
(just curious)

Thanks for the reply.

In article <>, Pszemol <> wrote:
>"Craig Bingman" <> wrote in message news:bp1s41$9he$...
>> pH electrodes tend to last longer in saltwater tanks than in
>> freshwater tanks, in my experience.

>So if I understand correctly, the main reason the electrode goes bad
>is the process of leaking fresh water to the inside of the probe and
>dissolving filling solution (osmosis)? In this case, if I buy refilable
>electrode and a bottle of 4M KCL I can revive the electrode every month?

Or salt leaking out, take your choice of perspectives. They are
equally valid. Refillable electrodes will last longer. The junction
will eventually foul in them, but one can occasionally find replaceable
junction electrodes too, which should go even longer.

>Understand. What do they exactly mean when they state "the filling
>solution is 4M KCL saturated with AgCl" - is AgCl dissolved in the
>filling solution or rather the filling solution is pure KCl and
>Ag comes from the silver wire inside the electrode?

The filling solution is saturated with Ag+ ions at that Cl- concentration.
The silver is in the +1 oxidation state, and doesn't come from the
internal wires. In a double-junction electrode, this is in the internal
(reference) part of the electrode.

The outer part that is in continuous intimate contact with the aquarium
water in a double-junction electrode is pure aqueous KCl. (At least that
is the way it starts out. Some silver migrates into the outer chamber
over time.)

>So the real acuracy of Pinpoint meter with electrode is 0.02
>decreased with regular (+/-)0.01 which comes from digital reading.
>Have you tested other meters claiming 0.01 acuracy? What about Milwaukee?
>(just curious)

I can't say that is true for all such meters, as I only examined one of
them. That one was plenty close enough for aquarium purposes.

This should all be taken with a grain or two of KCl, as I looked at them
in the 1995 to 1997 timeframe. Things could have changed since then,
in either direction.

I haven't looked at other aquarium grade meters. The pinpoint was close
enough to tell me what I needed to know, so I stopped looking there.

Craig

--
--