Hello,

I have read a lot of posts referring to Oxygen and also CO2 injections.
I am wondering why people do it, and whether or not its always good practice
to do it, or if only special setups require it.
In particular, would it allow you to overstock a tank?

Regards,

Gary.

From:	Morten
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sat, 1 Jan 2005 12:18:10 -0000

"Gary" wrote in message
news:qCaBd.36$Wz.19@text.news.blueyonder.co.uk...
> Hello,
>
> I have read a lot of posts referring to Oxygen and also CO2 injections.
> I am wondering why people do it, and whether or not its always good
practice
> to do it, or if only special setups require it.

Oxygen is for fish / live plants and CO2 is for plants nd to some extent
control of pH in some tanks.

> In particular, would it allow you to overstock a tank?

It's amazing how much Oxygen a single airstone and good surface agitation
can push into the water, it's not uncommon to fully saturate the water in
the tank using agitation and a single airstone. This does depend on
temperature though and if the temperature is vey high you may need to add
additional airstones...

On the fliside is that heavy agitation of the surface is bad for the added
CO2 because it will quickly establish equilibrium with the surrounding
athmosphere and you'll be back to sq1 for the CO2...

There is no link between the Oxigen carrier capacity and the CO2 carrier
capacity of the tank water, ie one does not affect the other (ie. by taking
it's place so a high O2 concentration does not lower the CO2 concentration,
but unless you're really carefull with the way you agitate the water the
added CO2 might just escape to the athmosphere as quickly as you can add
it...

But by adding CO2 to a heavy planted tank (and the required light) the
plants will 'excrete' lots of O2 and normally saturate the water when the
light is on so when the light is on (and the phottsynthese in the plants is
active) there will be lot of O2 in the water and it wont be necessary to add
more O2, but when the lights are turned off the plants actually starts to
use O2 and excrete CO2...

In a planted tank only this doesn't matter at all because the plants are
much better at adapting to the changing pH (due to changes in CO2
concentration and kH / gH of the tank) but in a fish / plant tank it
becomnes different matter.

/Morten

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From:	Ozdude
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sun, 2 Jan 2005 00:23:15 +1100

"Morten" wrote in message
news:41d69502$0$21318$db0fefd9@news.zen.co.uk...
> In a planted tank only this doesn't matter at all because the plants are
> much better at adapting to the changing pH (due to changes in CO2
> concentration and kH / gH of the tank) but in a fish / plant tank it
> becomnes different matter.

So does it follow to put a timer on an air pump and air stone and have it
come on when the lights go off, or sometime after? Of course it would have
to stop before the light timer turned the lights on in the a.m.

I am about to do a heavily planted tank, which may have extra DIY CO2
depending on a few other factors.

I have most of the plants and fish already in another tank and I don't see
the fish gasping at the surface in the morning or anything but I do worry
about the pH dropping too low at night, although there are only tetras in
there at the moment and a low morning pH may actually induce them to breed
;)

Does oxegenating raise pH, or just keep it stable?

Oz

From:	Morten
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sat, 1 Jan 2005 17:38:43 -0000

"Ozdude" wrote in message
news:41d6a42b$0$3436$afc38c87@news.optusnet.com.au...
>
> "Morten" wrote in message
> news:41d69502$0$21318$db0fefd9@news.zen.co.uk...
> > In a planted tank only this doesn't matter at all because the plants are
> > much better at adapting to the changing pH (due to changes in CO2
> > concentration and kH / gH of the tank) but in a fish / plant tank it
> > becomnes different matter.
>
> So does it follow to put a timer on an air pump and air stone and have it
> come on when the lights go off, or sometime after? Of course it would have
> to stop before the light timer turned the lights on in the a.m.

Withna bit of testing and trial and error that would work I think, but when
starting the air pump again you'll increase the surface agitation releasing
even more CO2 into the air, causing a further drop in pH. CO2 is caustic
when added to water (H2O + CO2 <=> HCO3(+) + OH(-) so more CO2 equals more
OH(-) which is very caustic...)

To decrease the change in pH when adding CO2 to your tank you would have to
increase the kH in the water, ie, add some Baking Soda (NaHCO3 or 2NaCO3
depending on who you ask) that will increase the kH which in turn keeps the
pH stable.

> I am about to do a heavily planted tank, which may have extra DIY CO2
> depending on a few other factors.

Yeast / sugar or bottled CO2 with a electronically controlled valve (linked
to pH, so you gotta know your kH before starting this venture) ?

Yeast / sugar is easy and cheap (a discarded 2L soda bottle, a bit air PVC
hose and an airstone will get you started), but requires some work replacing
the yeast mix when it's finished converting the sugars to alcohol (releasing
CO2 in the process) every 10-15 days depending on what type yeast, quantity
of sugar and temperature...

The bootled CO2 approach is expensive to setup, you'll need a 2 stage
preassure reducing valve that matches your CO2 bottle, and some hosing and a
airstone (or inlet into filter pump has been used to great extent) but when
setup is edad easy to use, especially if you make a CO2 controller with a pH
probe and a electronicly controlled phneumatic valve to open / close the
supply of CO2 depending on pH (with knowledge of the tanks kH off course
:-) )

The only long term work you have to do is to keep the pH probe alive and
calibrated but that's a 2 min. task every couple of months or so...

> I have most of the plants and fish already in another tank and I don't see
> the fish gasping at the surface in the morning or anything but I do worry
> about the pH dropping too low at night, although there are only tetras in
> there at the moment and a low morning pH may actually induce them to breed
> ;)

As long as the fishes ar not gasping after air at the surface you should be
fine, but if you really want tt to check you can buy O2 test kit at a good
LFS or go online and search for "O2 Oxygen test kit" that should get you
going...

> Does oxegenating raise pH, or just keep it stable?

Not directly, but if you have higher levels of CO2 in the water than normal
equilibrium with the athmosphere, then agitating the surface will lower the
dissolved CO2 in the tank and decrease your pH !

If you're not adding any CO2 into the tank then keeping the tank well aired
should keep the pH fluctuations to a minimun (because there's gonna be some
CO2 in the air as well as the O2) unless the kH is very low then it will be
all over the place depending on light, temperature, the neighbours 17year
old girl sunbathing on the lawn ect. simply because there's no buffer
capacity left to minimize the pH fluctuations...

/Morten

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From:	NetMax
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sat, 1 Jan 2005 13:01:43 -0500

"Morten" wrote in message
news:41d6e023$0$21323$db0fefd9@news.zen.co.uk...
>
> "Ozdude" wrote in message
> news:41d6a42b$0$3436$afc38c87@news.optusnet.com.au...
>>
>> "Morten" wrote in message
>> news:41d69502$0$21318$db0fefd9@news.zen.co.uk...
>> > In a planted tank only this doesn't matter at all because the plants
>> > are
>> > much better at adapting to the changing pH (due to changes in CO2
>> > concentration and kH / gH of the tank) but in a fish / plant tank it
>> > becomnes different matter.
>>
>> So does it follow to put a timer on an air pump and air stone and have
>> it
>> come on when the lights go off, or sometime after? Of course it would
>> have
>> to stop before the light timer turned the lights on in the a.m.
>
> Withna bit of testing and trial and error that would work I think, but
> when
> starting the air pump again you'll increase the surface agitation
> releasing
> even more CO2 into the air, causing a further drop in pH. CO2 is
> caustic
> when added to water (H2O + CO2 <=> HCO3(+) + OH(-) so more CO2 equals
> more
> OH(-) which is very caustic...)
>
> To decrease the change in pH when adding CO2 to your tank you would
> have to
> increase the kH in the water, ie, add some Baking Soda (NaHCO3 or
> 2NaCO3
> depending on who you ask) that will increase the kH which in turn keeps
> the
> pH stable.
>
>
>> I am about to do a heavily planted tank, which may have extra DIY CO2
>> depending on a few other factors.
>
> Yeast / sugar or bottled CO2 with a electronically controlled valve
> (linked
> to pH, so you gotta know your kH before starting this venture) ?
>
> Yeast / sugar is easy and cheap (a discarded 2L soda bottle, a bit air
> PVC
> hose and an airstone will get you started), but requires some work
> replacing
> the yeast mix when it's finished converting the sugars to alcohol
> (releasing
> CO2 in the process) every 10-15 days depending on what type yeast,
> quantity
> of sugar and temperature...
>
> The bootled CO2 approach is expensive to setup, you'll need a 2 stage
> preassure reducing valve that matches your CO2 bottle, and some hosing
> and a
> airstone (or inlet into filter pump has been used to great extent) but
> when
> setup is edad easy to use, especially if you make a CO2 controller with
> a pH
> probe and a electronicly controlled phneumatic valve to open / close
> the
> supply of CO2 depending on pH (with knowledge of the tanks kH off
> course
> :-) )
>
> The only long term work you have to do is to keep the pH probe alive
> and
> calibrated but that's a 2 min. task every couple of months or so...
>
>
>> I have most of the plants and fish already in another tank and I don't
>> see
>> the fish gasping at the surface in the morning or anything but I do
>> worry
>> about the pH dropping too low at night, although there are only tetras
>> in
>> there at the moment and a low morning pH may actually induce them to
>> breed
>> ;)
>
> As long as the fishes ar not gasping after air at the surface you
> should be
> fine, but if you really want tt to check you can buy O2 test kit at a
> good
> LFS or go online and search for "O2 Oxygen test kit" that should get
> you
> going...
>
>
>> Does oxegenating raise pH, or just keep it stable?
>
> Not directly, but if you have higher levels of CO2 in the water than
> normal
> equilibrium with the athmosphere, then agitating the surface will lower
> the
> dissolved CO2 in the tank and decrease your pH !
>
> If you're not adding any CO2 into the tank then keeping the tank well
> aired
> should keep the pH fluctuations to a minimun (because there's gonna be
> some
> CO2 in the air as well as the O2) unless the kH is very low then it
> will be
> all over the place depending on light, temperature, the neighbours
> 17year
> old girl sunbathing on the lawn ect. simply because there's no buffer
> capacity left to minimize the pH fluctuations...
>
>
> /Morten

Ozdude, that was a nice explanation by /Morten. Are you enjoying the
science lesson? A lot hinges (as you have seen) on your water's
buffering capacity (the kH), as this will suggest the methods to use.
Here my buffer is 16dkH (and my neighbours lawn is too far away ;~), so I
would have no concerns about pH crash (of course my kH is so high that
CO2 injection is basically worthless for me). Measure your water
supply's gH, kH and pH by pouring a glass of water and testing it the
following day. Then indicate what your planting aspirations are, and
then the newsgroup posters can provide options on how to reach your
objectives with your water.
--
www.NetMax.tk

From:	Ozdude
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sun, 2 Jan 2005 11:31:41 +1100

"NetMax" wrote in message
news:bABBd.69957$Tn1.2200191@news20.bellglobal.com...
> Ozdude, that was a nice explanation by /Morten. Are you enjoying the
> science lesson? A lot hinges (as you have seen) on your water's buffering
> capacity (the kH), as this will suggest the methods to use. Here my buffer
> is 16dkH (and my neighbours lawn is too far away ;~), so I would have no
> concerns about pH crash (of course my kH is so high that CO2 injection is
> basically worthless for me). Measure your water supply's gH, kH and pH by
> pouring a glass of water and testing it the following day. Then indicate
> what your planting aspirations are, and then the newsgroup posters can
> provide options on how to reach your objectives with your water.

He he, yes fortunately I can understand the science. kH has become apparent
and I am now wondering what mine actually is. I won't be able to test for it
for a month or so after the new tank is established so I'll leave it until
then, unless my LFS lady is willing to test some water for me. I am usually
very patient so there is no rush to do this for me.

My main thing is to cycle the tank and get everything healthy before I start
tinkering with the environment for anything.

If it naturally grows plants (i.e. no die off and some growth) and the fish
are comfortable, it may be a case of "if ain't broke, don't fix it", which
I'm hoping, but we'll have to see.

My local tap water here seems to buffer okay (only a subjective
observation), so as I said first things first, then we'll move on if
necessary.

I am just trying to be as prepared as possible for the largest tank I've
ever had, which is a small one in comparison to some ;)

Oz

From:	Ozdude
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sun, 2 Jan 2005 11:22:00 +1100

"Morten" wrote in message
news:41d6e023$0$21323$db0fefd9@news.zen.co.uk...
>> Does oxegenating raise pH, or just keep it stable?
>
> Not directly, but if you have higher levels of CO2 in the water than
> normal
> equilibrium with the athmosphere, then agitating the surface will lower
> the
> dissolved CO2 in the tank and decrease your pH !
>
> If you're not adding any CO2 into the tank then keeping the tank well
> aired
> should keep the pH fluctuations to a minimun (because there's gonna be
> some
> CO2 in the air as well as the O2) unless the kH is very low then it will
> be
> all over the place depending on light, temperature, the neighbours 17year
> old girl sunbathing on the lawn ect. simply because there's no buffer
> capacity left to minimize the pH fluctuations...

Thanks. Things to mindful of when I venture into this.

Oz

From:	Gary
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sat, 01 Jan 2005 12:48:52 GMT

> In a planted tank only this doesn't matter at all because the plants are
> much better at adapting to the changing pH (due to changes in CO2
> concentration and kH / gH of the tank) but in a fish / plant tank it
> becomnes different matter.
>
>
> /Morten

Thanks Morton, I will need to read your post a few times, just to make sure
I understand.
In my Cichlid setup, I have no plants. It is very rocky, with violent
surface movement. The tank is 2ft deep, so the surface movement does not
have much of an impact on the lower areas of the tank. When you refer to
Airstones, are you talking about a pump which attaches to a tube creating
bubbles? If so, I have 2 x 24" running along the back wall of the tank. It
looks very nice, and creates more surface movement.

How does one measure the oxygen levels in a tank?

Regards,

Gary.

From:	NetMax
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sat, 1 Jan 2005 12:41:14 -0500

"Gary" wrote in message
news:U_wBd.612$GG1.192@text.news.blueyonder.co.uk...
>> In a planted tank only this doesn't matter at all because the plants
>> are
>> much better at adapting to the changing pH (due to changes in CO2
>> concentration and kH / gH of the tank) but in a fish / plant tank it
>> becomnes different matter.
>>
>>
>> /Morten
>
>
> Thanks Morton, I will need to read your post a few times, just to make
> sure I understand.
> In my Cichlid setup, I have no plants. It is very rocky, with violent
> surface movement. The tank is 2ft deep, so the surface movement does
> not have much of an impact on the lower areas of the tank. When you
> refer to Airstones, are you talking about a pump which attaches to a
> tube creating bubbles? If so, I have 2 x 24" running along the back
> wall of the tank. It looks very nice, and creates more surface
> movement.
>
> How does one measure the oxygen levels in a tank?
>
> Regards,
>
> Gary.

CO2 injection has no application in a non-planted tank, unless you were
trying to reduce the pH (and there are easier ways to do that, if it was
really warranted).

I think your application is to maximize the oxygen levels in the tank,
and this is done by i) causing a sufficient turbulence across the water
surface to continual bring low-O2 water in contact with the air, ii)
causing a vertical turbulence in the tank bringing low-O2 water from the
bottom of the tank to the surface, to be re-oxygenated. Other variables
are temperature (the warmer the water, the less O2 can be dissolved into
it), fish-load (more fish = more respiration), fish metabolism (very
active fish consume more O2 than sedate fish, also related to water
temperature), waste production (related to metabolism, related to food
supply).

A simple method to determine the O2 reserve in your tank is to turn off
all the filters, air pumps, water pumps etc, and observe their behavior.
They will immediately slow down and get jittery (from the deafening
silence), but after a while their slower speeds can be attributed to the
O2 levels, especially as they start moving into the upper levels of the
tank (this test can be hazordous to some fish). If all your fish were
sucking air within an hour, you would be in bad shape.

There are O2 meters, but I've never used them. Ordinarily, O2 is not a
problem unless you lose electricity. If with electricity, you reach a
bio-load which is consuming the O2 faster than it can dissolve back into
the water, you would probably have encountered many other problems first,
such as biological filtration (ammonia or nitrites measured, or excessive
nitrates). hth
--
www.NetMax.tk

From:	Edward Cowling
Subject:	Re: Oxygen & CO2 Injection....
Date:	Mon, 03 Jan 2005 12:09:56 GMT

From:	Corncrake
Subject:	Re: Oxygen & CO2 Injection....
Date:	Tue, 04 Jan 2005 01:19:57 GMT

On Mon, 03 Jan 2005 12:09:56 GMT, "Edward Cowling" wrote:
>I do have a pet hate about aquarists turning into chemists
>in recent years :-)

I dont :-) I like learning about water chemistry;-)

> It seems the industry is constantly finding
>ways for us to spend lots more money on keeping our fish.

I agree.
But if aquarists dont pay attention and learn "wotitsallabout", then
can you blame bigindustry for exploiting a percieved market ?
Surely the defence is that aquarists (or their friends) should aquire
the knowledge to be able to raise two fingers to the industry ??

>Personally I don't own a water testing kit

I do, but only for my own education.
I enjoyed learning water chemistry many years ago ( just a little
while after I enjoyed the chemistry of making modest bangs ;-) )

> I have healthy fish who constantly produce young, and
>every week I trim out a bucket full of lush green plants.

Congratulations,me too, that's what it's all about.

>Just be an aquarist who enjoys keeping fish, and leave oxygen
>injection to the rocket scientists :-)

ah! now if you take a bit of carbon, saltpetre and sulphur
or some sulphur and zinc dust, a rocket is well within,,
oh,,sorry,, OT.

From:	Dave Dew
Subject:	Re: Oxygen & CO2 Injection....
Date:	Tue, 04 Jan 2005 11:57:31 GMT

"Corncrake" wrote in message
news:41d9ea55.3776522@text.news.ntlworld.com...
> On Mon, 03 Jan 2005 12:09:56 GMT, "Edward Cowling" wrote:
> >I do have a pet hate about aquarists turning into chemists
> >in recent years :-)

Snip, Snip,

> >Just be an aquarist who enjoys keeping fish, and leave oxygen
> >injection to the rocket scientists :-)
>
> ah! now if you take a bit of carbon, saltpetre and sulphur
> or some sulphur and zinc dust, a rocket is well within,,
> oh,,sorry,, OT.
>
>
>
That is absolutely right. Rocket science is quite simple -
'Every action has an equal and opposite reaction'.
What is difficult is rocket technology.

;-)

Dave.

From:	NetMax
Subject:	Re: Oxygen & CO2 Injection....
Date:	Mon, 3 Jan 2005 10:01:57 -0500

"Edward Cowling" wrote in message
news:oCaCd.800$v82.596@fe3.news.blueyonder.co.uk...
>
> "Gary" wrote in message
> news:qCaBd.36$Wz.19@text.news.blueyonder.co.uk...
>> Hello,
>>
>> I have read a lot of posts referring to Oxygen and also CO2
>> injections.
>> I am wondering why people do it, and whether or not its always good
>> practice to do it, or if only special setups require it.
>
> I do have a pet hate about aquarists turning into chemists
> in recent years :-) It seems the industry is constantly finding
> ways for us to spend lots more money on keeping our fish.
>
> Personally I don't own a water testing kit, or any shelf full
> of patent remedies. I just change a third of the water every
> week and keep the filters clean.... about 2 hours a week of
> work. I have healthy fish who constantly produce young, and
> every week I trim out a bucket full of lush green plants.
>
> Just be an aquarist who enjoys keeping fish, and leave oxygen
> injection to the rocket scientists :-)
>
> --
> Edward Cowling - London - UK

LOL here here! (or is it hear hear?). But there is a middle road. I
find the test kits essential in establishing what my source water is like
(to match fish to it if needed), and for monitoring periodically what the
aquarium's trends are (if there is a trend), and if my maintenance regime
is adequate.

I hate the idea that new aquarists feel they need to learn how to inject
CO2, remove phosphates, make their own PMDD, engineer new lighting and
master the art of filtration. There *is* all sorts of interesting fun
that you can have, but for newbies?? i) cycle your tank, ii) familiarize
yourself with your water, the species of fish you will be adding and how
they relate to their tank mates, iii) meet their requirements as they
grow. After that you can go down any of the specialty roads, or stay
right where you are and still enjoy the hobby (jmho).
--
www.NetMax.tk

From:	Ozdude
Subject:	Re: Oxygen & CO2 Injection....
Date:	Tue, 4 Jan 2005 13:45:59 +1100

"NetMax" wrote in message
news:B7dCd.8997$P%3.636544@news20.bellglobal.com...
> I hate the idea that new aquarists feel they need to learn how to inject
> CO2, remove phosphates, make their own PMDD, engineer new lighting and
> master the art of filtration. There *is* all sorts of interesting fun
> that you can have, but for newbies?? i) cycle your tank, ii) familiarize
> yourself with your water, the species of fish you will be adding and how
> they relate to their tank mates, iii) meet their requirements as they
> grow. After that you can go down any of the specialty roads, or stay
> right where you are and still enjoy the hobby (jmho).

Agreed. I had this sort of realisation yesterday whilst doing a water change
on my current tank.

I am interested in *what* could cause a problem, but then realised if it
ain't broke don't fix it applies.

If anything after reading in here and reading your web site (which is a
jewel btw;) I am starting to think my tank is actually suffering old tank
syndrome, as the I remembered that the gravel was given to me by a friend
who doesn't use filtration and doesn't do water changes, and I didn't wash
it all that well (in ignorance - seeing it had come out of an aqauraium in
the first place). I then placed a 1 cm layer of brand new washed gravel over
it later on, but it's all pointing towards OTS and I have this group to
thank for knowledge.

However, I do believe that getting to know your water and correcting any
glaring things which may cause fish stress or death is the first step and
all the other stuff is basically optional.

Could you know too much I wonder?

Keep it simple in 2005! :)

Oz

From:	Richard Torrens (news)
Subject:	Re: Oxygen & CO2 Injection....
Date:	Sun, 02 Jan 2005 14:54:21 +0000 (GMT)

In article ,
Gary wrote:
> Hello,

> I have read a lot of posts referring to Oxygen and also CO2 injections.
> I am wondering why people do it, and whether or not its always good
> practice to do it, or if only special setups require it. In particular,
> would it allow you to overstock a tank?

If has been proposed that submerged water plants take in significant CO2
via their roots.

Certainly roots are for more than just anchorage: many plants do better
when rooted in a good compost.

A well-established aquarium substrate will have lots of organic matter,
bacteria etc in the gravel. If you disturb the gravel in such a tank, you
will release bubbles of mainly CO2.

Certainly plants need a long time to get established in a new tank and
part of this could well be CO2 buildup in the gravel.

My 350L tank had not so many fish (the 18" type-track would eat them!) and
a heavy plant growth. It has large quantities of apple snails - which get
copiously fed. It also has large quantities of freshwater worms living
quite happily in the gravel. I am of the opinion that the worms are a
significant advantage in keeping the gravel sweet and allowing proper
bacterial action.

Has anyone any relayed experiences?

--
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