Boiled Water

[Douglas Barber]

I read somewhere that you can soften water by boiling it, and decided to
do this as an experiment with my well water here in Crisfield, MD (about
1/2 mile from the Chesapeake Bay).

Before boiling, my water was 10 degrees (not ppm) general hardness, with
a pH of 7.8. After boiling for about 2 hours and cooling, it was 4.5
degrees general hardness and (this is the part that mystifies me) over
8.8 pH.

I don't have a test kit to measure carbonate hardness.

Any ideas what's going on here? If I add this water to my aquarium,
which is about 50/50 unboiled well water/distilled water with a net 5
degrees general hardness and pH pretty stable at about 7.8, is it going
to raise the pH of the aquarium by as much as I would intuitively think
it would?

[JTech]

> I read somewhere that you can soften water by boiling it, and decided to
> do this as an experiment with my well water here in Crisfield, MD (about
> 1/2 mile from the Chesapeake Bay).
>
> Before boiling, my water was 10 degrees (not ppm) general hardness, with
> a pH of 7.8. After boiling for about 2 hours and cooling, it was 4.5
> degrees general hardness and (this is the part that mystifies me) over
> 8.8 pH.
>
> I don't have a test kit to measure carbonate hardness.
>
> Any ideas what's going on here? If I add this water to my aquarium,
> which is about 50/50 unboiled well water/distilled water with a net 5
> degrees general hardness and pH pretty stable at about 7.8, is it going
> to raise the pH of the aquarium by as much as I would intuitively think
> it would?
>
As you saw there, it is backwards. boiling it drives off the disolved co2,
making it a little higher ph. when you put it into the tank, it will
re-absorb some co2 from fish etc. and balance out at what you have in your
tank now. All the boiling did was (far as good), kill and germs and
bacteria that may be in the well water. fwiw..

[Morten]

"Douglas Barber" > wrote in message
...
> I read somewhere that you can soften water by boiling it, and decided to
> do this as an experiment with my well water here in Crisfield, MD (about
> 1/2 mile from the Chesapeake Bay).
>
> Before boiling, my water was 10 degrees (not ppm) general hardness, with
> a pH of 7.8. After boiling for about 2 hours and cooling, it was 4.5
> degrees general hardness and (this is the part that mystifies me) over
> 8.8 pH.

Boiling will not decrease the mineral content in the water it will increase
it if anything. When the water boils the only thing that leaves is water (as
steam) leaving slightly less water to the same amount of minerals so the
concentration increases.

You may find that some of the minerals will deposit in the container you
used to boil the water in the first place, but that won't change much.

The pH increases because by boiling the water you will drive some of the
dissolved CO2 out of the water which will cause the pH to go down. It will
soon reabsorb the CO2 from the air and the pH will return to the values
before you boiled the water.


> I don't have a test kit to measure carbonate hardness.

> Any ideas what's going on here? If I add this water to my aquarium,
> which is about 50/50 unboiled well water/distilled water with a net 5
> degrees general hardness and pH pretty stable at about 7.8, is it going
> to raise the pH of the aquarium by as much as I would intuitively think
> it would?


Just put an airstone in the water for a wef ours and you will find that it
has returned to normal.


Boiling really doesn't do much (besides waste a lot of energy) to your water
unless you have a lot of baterual growth / contamination that will be killed
off in the process, oh, and chlorine will go to (but there are better ways
of getting rid of that)


Does your water come from a contaminated well, that will require the water
to be boiled to be healthy to use in a fish tank.


Regards

Morten




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[NetMax]

"Douglas Barber" > wrote in message
...
> I read somewhere that you can soften water by boiling it, and decided
to
> do this as an experiment with my well water here in Crisfield, MD
(about
> 1/2 mile from the Chesapeake Bay).

I'm not sure if the effect is on the gH or the kH, but I've read the same
thing. It's not practical as a routine, but it makes an interesting
experiment.

> Before boiling, my water was 10 degrees (not ppm) general hardness,
with
> a pH of 7.8. After boiling for about 2 hours and cooling, it was 4.5
> degrees general hardness and (this is the part that mystifies me) over
> 8.8 pH.
>
> I don't have a test kit to measure carbonate hardness.

Well, your gH dropped (indication of less calcium, magnesium etc). Your
pH will probably return to normal with aeration, and if it does, then I
think that you could assume your kH was unchanged, but it would be
interesting to measure the kH to be sure.

> Any ideas what's going on here? If I add this water to my aquarium,
> which is about 50/50 unboiled well water/distilled water with a net 5
> degrees general hardness and pH pretty stable at about 7.8, is it going
> to raise the pH of the aquarium by as much as I would intuitively think
> it would?

My guess is that it would not effect your pH or kH, but the gH would
average out, but it's just a guess :o) Try it with an equal sample of
tank water.

I don't know the mechanism at work when water is softened by boiling, so
the effect may not be permanent, or perhaps it changes state so it does
not register with the test kit and perhaps the fish (?).

NetMax

[Michi Henning]

"NetMax" > wrote in message
. ..

> I don't know the mechanism at work when water is softened by boiling, so
> the effect may not be permanent, or perhaps it changes state so it does
> not register with the test kit and perhaps the fish (?).

As far as I know, boiling causes the bicarbonates in the water to
precipitate out. This releases CO2 and binds some of the kations,
such as Mg and Ca. Since a GH test measures kations, GH drops.
And because CO2 is driven out, pH rises, and KH drops. If you
run CO2 through the boiled water, the previous balance quickly
re-establishes itself.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com

[NetMax]

"Michi Henning" > wrote in message
...
> "NetMax" > wrote in message
> . ..
>
> > I don't know the mechanism at work when water is softened by boiling,
so
> > the effect may not be permanent, or perhaps it changes state so it
does
> > not register with the test kit and perhaps the fish (?).
>
> As far as I know, boiling causes the bicarbonates in the water to
> precipitate out. This releases CO2 and binds some of the kations,
> such as Mg and Ca. Since a GH test measures kations, GH drops.
> And because CO2 is driven out, pH rises, and KH drops. If you
> run CO2 through the boiled water, the previous balance quickly
> re-establishes itself.

Thanks for that Michi.

NetMax

> Cheers,
>
> Michi.
>
> --
> Michi Henning Ph: +61 4 1118-2700
> ZeroC, Inc. http://www.zeroc.com
>

[Charles]

On Thu, 11 Mar 2004 12:29:11 GMT, "Michi Henning" >
wrote:

>"NetMax" > wrote in message
. ..
>
>> I don't know the mechanism at work when water is softened by boiling, so
>> the effect may not be permanent, or perhaps it changes state so it does
>> not register with the test kit and perhaps the fish (?).
>
>As far as I know, boiling causes the bicarbonates in the water to
>precipitate out. This releases CO2 and binds some of the kations,
>such as Mg and Ca. Since a GH test measures kations, GH drops.
>And because CO2 is driven out, pH rises, and KH drops. If you
>run CO2 through the boiled water, the previous balance quickly
>re-establishes itself.
>
>Cheers,
>
>Michi.


with a bit of variation.

bicarbonate hardness, also called temporary hardness, can be reduced
by boiling. The calcium and magnesium bicarbonates are converted to
calcium and magnesium carbonates, much less soluble, which settle out
on the boiling container as lime scale. if the boiled water is then
moved into a separate container, the calcium and magnesium carbonates
are left behind and the total hardness has been reduced.

so called permanent hardness is from calcium and magnesium sulfates
which are unaffected by boiling.
--

- Charles
-
-does not play well with others

[Michi Henning]

"Charles" > wrote in message
...

> with a bit of variation.
>
> bicarbonate hardness, also called temporary hardness, can be reduced
> by boiling. The calcium and magnesium bicarbonates are converted to
> calcium and magnesium carbonates, much less soluble, which settle out
> on the boiling container as lime scale. if the boiled water is then
> moved into a separate container, the calcium and magnesium carbonates
> are left behind and the total hardness has been reduced.
>
> so called permanent hardness is from calcium and magnesium sulfates
> which are unaffected by boiling.

Thanks for the clarification, Charles. You are right of course -- for the
previous balance to be reestablished after adding CO2, you would have
to boil the water in the tank (which I doubt all that many people will
do ;-)

I guess boiling water isn't all that useful for fishkeeping though -- usually,
people are interested in dropping KH and GH together, but boiling
produces water that has quite a large difference between the two, with
a low KH and a (comparatively) high GH.

BTW, normally GH is always greater than KH, because

GH - KH = NKH

or

Total hardness - carbonate hardness = non-carbonate hardness

(You can find this formula in a lot of older books on fish keeping.)

However, some waters measure a KH greater than GH, which appears
impossible. The reason is that a GH test measures alkaline earth metal
ions, that is, Mg++, Ca++, and Sr++. On the other hand, a
KH test measures carbonate ions and hydrogen carbonate ions
(CO3-- and HCO3-).

So, if KH is greater than GH (there are more carbonate and hydrogen
carbonate ions in the water than alkaline earth metal ions), the excess
CO3-- and HCO3- ions are bound by alkali metal ions (Na+, and
K+). So, if KH measures greater than GH, that is simply an artifact
of the measuring technique that is used. You could also say that
GH (which is the German abbreviation for "total hardness") is a
misnomer, because it doesn't measure all of the hardness, just
some of it.

Historically, all this confusion is caused by the fact that, prior to modern
tests, people added calibrated soap solution to a water sample and
kept shaking until a steady head of foam was formed. The amount
of soap used was taken as measure of the hardness of the water because
Mg and Ca ions bind with the soap and precipitate out so, the
more soap was used, the "harder" the water was. (This method was
in use by aquarists until about the mid-fifties.) Then, later, people
found out that some of the hardness disappears when when you
boil water. This removable component of the "total" hardness
was called "temporary hardness" or "carbonate hardness" because
it is caused by bicarbonates. Then people came up with the
idea that GH = KH + NKH which, strictly speaking, is wrong
and has caused endless confusion for aquarists who found water
with a KH > GH.

Modern chemistry avoids the entire issue by not talking about
hardness at all and instead simply quoting the ion concentrations.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com