Swimming pool test kit for pH ?

[George Pontis]

Seeking some consensus on a good and reliable way to measure pH in the freshwater
aquarium!

I have tried several aquarium test kits, Red Sea (low range) and Tetra (low range)
come to mind. I find it error-prone and generally inaccurate to try comparing
color reflected off a printed card with light transmitted through the test vial.
Different lighting can change the apparent reading. The Tetra kit had color
standards spaced at 0.5pH units apart. Probably OK for telling the difference
between 7.0 and 7.5.

Mardel test strips are convenient and not hard to read. Somewhat more expensive
than the liquid reagent kits. Accuracy ?

I also tried a couple of handheld electronic pH meters. These have the potential
to be very good, but in practice they produce confusing readings. I believe that
my water has too low a conductivity for these units, though maybe a real
laboratory model would do well.

So far the best tester that I have tried is a swimming pool kit. The particular
one that I have at hand is made by Taylor. It has square vials for chlorine and pH
molded into a block, with transparent printed color references next to each vial.
This kit was cheap (about $8), provides a lot of tests, and is very easy to read.
Comparison standards are at 6.8, 7.2, 7.5, 7.8, 8.2. I find it possible to
interpolate a reading between the standards and actually believe that the answer
could be meaningful. The local swimming pool supply house has deluxe kits with
standards every 0.2pH unit.

What would you prefer for a good pH reading ?

[blank]

"George Pontis" > wrote in message

> What would you prefer for a good pH reading ?

http://www.caprockdev.com/HI98129.htm

[George Pontis]

In article >,
says...
>
> "George Pontis" > wrote in message
>
> > What would you prefer for a good pH reading ?
>
> http://www.caprockdev.com/HI98129.htm
>


That looks like a fine unit, a step up from my Omega Litmustik III which reads pH
and temperature. Neither of them says in the specs how accuracy is at low
conductivities. I know that there is such an effect, and the Omega doesn't cut it
for soft aquarium water or our tap water.

Have you found good results with this model ?

[NetMax]

"blank" > wrote in message
...
>
> "George Pontis" > wrote in message
>
> > What would you prefer for a good pH reading ?
>
> http://www.caprockdev.com/HI98129.htm
>


blank: that's a nice piece of electronics :-).

George: IMO There is very little requirement to be able to make precise
pH measurements for fish. Your objective is convenience and
repeatability. Pour a glass of water and check the pH after 24 hours.
This is your baseline. You now want relative accuracy and not
necessarily absolute accuracy. Whether your measurement method is 0.1pH
or 1.0pH accurate, your interest is in being able to detect variance
(aquarium to source) of about 0.5pH (which is the allowable drift over
24 - 48 hours for most fish).

ps: if using the liquid reagents, hold the tube in a source of indirect
natural light and look directly down the top from above, for a better
colour match.

pss: women purportedly have better colour acuity than men, so get them to
match the colours.
--
www.NetMax.tk

[Justin Boucher]

"pss: women purportedly have better colour acuity than men, so get them to
match the colours."

Is that why men's shirts only come in a total of 5 colors while womens
blouses have 27 different shades of red alone? =)

"Its purple."
"That's not purple, Dear. That's Fuchia. This one's Purple."
"I thought that one was Fuchia."
"No, that one's Lavender."
"Can I go to the electronics department?"

"NetMax" > wrote in message
...
> "blank" > wrote in message
> ...
> >
> > "George Pontis" > wrote in message
> >
> > > What would you prefer for a good pH reading ?
> >
> > http://www.caprockdev.com/HI98129.htm
> >
>
>
> blank: that's a nice piece of electronics :-).
>
> George: IMO There is very little requirement to be able to make precise
> pH measurements for fish. Your objective is convenience and
> repeatability. Pour a glass of water and check the pH after 24 hours.
> This is your baseline. You now want relative accuracy and not
> necessarily absolute accuracy. Whether your measurement method is 0.1pH
> or 1.0pH accurate, your interest is in being able to detect variance
> (aquarium to source) of about 0.5pH (which is the allowable drift over
> 24 - 48 hours for most fish).
>
> ps: if using the liquid reagents, hold the tube in a source of indirect
> natural light and look directly down the top from above, for a better
> colour match.
>
> pss: women purportedly have better colour acuity than men, so get them to
> match the colours.
> --
> www.NetMax.tk
>
>

[Peter Ashby]

George Pontis > wrote:

> Seeking some consensus on a good and reliable way to measure pH in the
> freshwater aquarium!
>
> I have tried several aquarium test kits, Red Sea (low range) and Tetra
> (low range) come to mind. I find it error-prone and generally inaccurate
> to try comparing color reflected off a printed card with light transmitted
> through the test vial. Different lighting can change the apparent reading.
> The Tetra kit had color standards spaced at 0.5pH units apart. Probably OK
> for telling the difference between 7.0 and 7.5.
>
> Mardel test strips are convenient and not hard to read. Somewhat more
> expensive than the liquid reagent kits. Accuracy ?
>
> I also tried a couple of handheld electronic pH meters. These have the
> potential to be very good, but in practice they produce confusing
> readings. I believe that my water has too low a conductivity for these
> units, though maybe a real laboratory model would do well.
>
> So far the best tester that I have tried is a swimming pool kit. The
> particular one that I have at hand is made by Taylor. It has square vials
> for chlorine and pH molded into a block, with transparent printed color
> references next to each vial. This kit was cheap (about $8), provides a
> lot of tests, and is very easy to read. Comparison standards are at 6.8,
> 7.2, 7.5, 7.8, 8.2. I find it possible to interpolate a reading between
> the standards and actually believe that the answer could be meaningful.
> The local swimming pool supply house has deluxe kits with standards every
> 0.2pH unit.
>
> What would you prefer for a good pH reading ?

A calibrated lab pH meter which is what I use at work for preference, if
that isn't available or not appropriate we use the next best thing, pH
papers. We have specs that will do very accurate colour determinations
but I know of noone using them for pH though I suppose the chemists
might.

So lacking the cash or will for a lab pH meter at home (not to mention
the calibration issues) I use eSha test strips and have no reason to
doubt them, I saw what looked like an identical set from Tetra recently.
I find comparing reflected light from the strip with reflected light
from the printed reference much easier than with liquid tests. they also
give you nitrates, nitrites, GH and KH. But as NetMax says,
comparability between tesst is more important than absolute accuracy, I
don't really need to know if the water is pH6.7 or 6.8, I do need to
know if it has changed to around 7.2. The test strips are so much more
convenient to use I tend to test more often, I think this is a good
thing.

Peter
--
Add my middle initial to email me. It has become attached to a country

[blank]

"George Pontis" > wrote in message
...
> In article >,
> says...
> >
> > "George Pontis" > wrote in message
> >
> > > What would you prefer for a good pH reading ?
> >
> > http://www.caprockdev.com/HI98129.htm
> >
>
>
> That looks like a fine unit, a step up from my Omega Litmustik III which
reads pH
> and temperature. Neither of them says in the specs how accuracy is at low
> conductivities. I know that there is such an effect, and the Omega
doesn't cut it
> for soft aquarium water or our tap water.
>
> Have you found good results with this model ?

Yes, I use it daily at work to test potting mix, and bring it home on
weekends for my fish. But you must follow the instructions exactly and be
careful not to drop it. Here in Australia, I have found Hanna to be an
excellent company to deal with. We have tried cheaper meters but find that
the Hanna models are worth the money

[George Pontis]

In article >,
says...
>
> "George Pontis" > wrote in message
> ...
> > In article >,
> > says...
> > >
> > > "George Pontis" > wrote in message
> > >
> > > > What would you prefer for a good pH reading ?
> > >
> > > http://www.caprockdev.com/HI98129.htm
> > >
> >
> >
> > That looks like a fine unit, a step up from my Omega Litmustik III which
> reads pH
> > and temperature. Neither of them says in the specs how accuracy is at low
> > conductivities. I know that there is such an effect, and the Omega
> doesn't cut it
> > for soft aquarium water or our tap water.
> >
> > Have you found good results with this model ?
>
> Yes, I use it daily at work to test potting mix, and bring it home on
> weekends for my fish. But you must follow the instructions exactly and be
> careful not to drop it. Here in Australia, I have found Hanna to be an
> excellent company to deal with. We have tried cheaper meters but find that
> the Hanna models are worth the money
>

It is about twice the price of the Litmustik, but it also has conductivity. Being
fully waterproof is a good thing too. As far as aquarium use, one can reasonably
hope that the pH electrode will last a long time since replacements are a bit
costly. Though probably overkill for the aquarium, this sure has some appeal to
the scientist in us. What a great gift it would be for the aquarist that has
everything.

[George Pontis]

In article >,
says...
> ...
>
> So lacking the cash or will for a lab pH meter at home (not to mention
> the calibration issues) I use eSha test strips and have no reason to
> doubt them, I saw what looked like an identical set from Tetra recently.
> I find comparing reflected light from the strip with reflected light
> from the printed reference much easier than with liquid tests. they also
> give you nitrates, nitrites, GH and KH. But as NetMax says,
> comparability between tesst is more important than absolute accuracy, I
> don't really need to know if the water is pH6.7 or 6.8, I do need to
> know if it has changed to around 7.2. The test strips are so much more
> convenient to use I tend to test more often, I think this is a good
> thing.
>

I have not seen those strips for sale in these parts, but will get a pack and try
them out if they become available. Your point about convenience is right on, and
even though I enjoy the hands-on science I find a lot to like about the strips. So
does my 7 year old daughter, who wouldn't be comfortable or safe enough with
liquid reagents.

BTW, congrats on your clever email obfuscation. It will be quite a while before
the spam machines can decode that one.

[George Pontis]

In article >,
says...
> ...
>
> George: IMO There is very little requirement to be able to make precise
> pH measurements for fish. Your objective is convenience and
> repeatability. Pour a glass of water and check the pH after 24 hours.
> This is your baseline. You now want relative accuracy and not
> necessarily absolute accuracy. Whether your measurement method is 0.1pH
> or 1.0pH accurate, your interest is in being able to detect variance
> (aquarium to source) of about 0.5pH (which is the allowable drift over
> 24 - 48 hours for most fish).

Understood. But of all the choices available to us, why go with ones that have so
much reading uncertainty as the liquid pH -vs- printed paper. The swimming pool
test kit is really cheap per test and easy to read and meets your standard for
providing good relative measurements. The absolute pH of the swimming pool is
important, so I suppose that the test kits are held to a higher standard. I have
not seen any pool pH test kits that use transmitted (liquid vial) -vs- reflected
(paper) measurements.

> ps: if using the liquid reagents, hold the tube in a source of indirect
> natural light and look directly down the top from above, for a better
> colour match.

I have tried this to good effect when the test gives different hues. pH is pretty
subtle in hue within a small range, but it does help interpret the reading
sometimes. If Tetra and other manufacturers would spend another couple of cents to
print their colors on a transparent sheet instead of paper it would be so much
easier to get a consistent result.

Some of the tests, like Tetra O2, have only color saturation as a result. In those
tests one cannot change the depth through the vial without directly affecting the
reading. And that is a test where some absolute accuracy is needed!

>
> pss: women purportedly have better colour acuity than men, so get them to
> match the colours.
>

I have two daughters 6 and 7 yrs old. They both like reading the test results and
are pretty quick to come to an answer. If we are not unified then we just hold the
test tube and card n a different light until the problem goes away !

[Peter Ashby]

George Pontis > wrote:

>
> BTW, congrats on your clever email obfuscation. It will be quite a while
> before the spam machines can decode that one.

Thanks, I was bored with my previous one a few months ago. Variety is
the spice of life after all.

Peter
--
Add my middle initial to email me. It has become attached to a country