NEW? way to add CO2

[Lord Don]

"NetMax" > wrote in message
.. .
> Has anyone heard of controlling the water's pH/CO2 level by controlling
> the CO2 concentration *above* the water surface rather than by pumping it
> through the tank's water in little bubbles?
>

The airline from my simple yeast co2 setup bubbles air into a floating
upside down chinese take away container. May sound lame but it takes up half
the 2 foots surface area and seems to help. The clear plastic lets 'some'
light through but there is a reduction. I am working on a glass shelf that
will act almost like a reverse weir. This will allow me to have the surface
completely open to normal air and have another fake surface below that with
a pure co2 atmosphere.
stuffed if I can explain this but it's been easy enuf to do, just looks ugly
as sin. WOrking on that and the hood should cover it nicely.

[NetMax]

Has anyone heard of controlling the water's pH/CO2 level by controlling
the CO2 concentration *above* the water surface rather than by pumping it
through the tank's water in little bubbles?

Aeration and turbulence causes the dissolved gases in the water to
equalize with the atmosphere at the contact points (water's surface and
surface area of any bubbles pushed through). If a relatively air-tight
cover were installed above a tank, then CO2 could be pumped into the
cover (ie: from a pressurised CO2 tank), effectively making the cover an
environmental chamber. If the air pump's intakes (or the air pumps
themselves) were also in this 'chamber', you could have as much bubbles
as you liked (without any negative effects on CO2 levels, actually it
would have a net positive effect in a heavily planted tank during peak
consumption).

This design precludes the use of any open loop devices (no HOB
powerfilters, no sump filters, no trickle filters), so filtration would
either need to be inside (internal canisters, UGF, RUGF, sponge etc) or
closed loop (external canisters). That's not too bad as it still leaves
lots of options.

From an air quality view, more of the CO2 would be converted into plant
growth than escaping into the atmosphere for us to breathe as happens now
(assuming some sealing around the chamber), so this is a positive aspect.
Accordingly, CO2 usage and operating costs would decrease (greater
efficiencies to achieve comparable growth).

My understanding is that CO2 gas is inert (non-oxidizing), so the big
concern would be the acidic condensation on the inside of the cover (from
the carbonic acid).

As an aside, would it be better if we used a known fixed pressurised
CO2 - nitrogen mixture? Current commercial/industrial CO2 applications
are for things like cooling, welding, carbonizing drinks or providing an
inert atmosphere, so the actual mix of gases might not be ideal for
aquatic plant growth (I'm just a wealth of good questions, but this
newsgroup tends to be a wealth of good answers :o).

One unknown potential to using an environmental chambers as an aquarium
hood is that CO2 testers might be cheaper than pH testers, though we
would probably still need to monitor the water's pH (unless we monitored
the kH and CO2 levels concurrently). I haven't thought this part through
yet, but it would be great to have a simple fool-proof way to at-a-glance
know if your tank's pH was getting too low, so that you would dial back
your CO2 concentration.

On the down side, the aquarium cover would probably be larger (unsightly)
and require more sealing (around electrical connections, hoses, heater
wires and tank edge). As drawbacks, these are not huge. I've built
custom covers out of wood which could have been upgraded to these
requirements with some fibreglass or epoxy coating inside and some
weather-stripping along the edge. The seal does not and should not be
perfect as the chamber will need to replenish trace gases consumed (ergo
my CO2+N question on the pressurised tanks).

Anyways, I thought I'd percolate this by the experts ;~).
--
www.NetMax.tk

[Steve]

NetMax wrote:
> Has anyone heard of controlling the water's pH/CO2 level by controlling
> the CO2 concentration *above* the water surface rather than by pumping it
> through the tank's water in little bubbles?
>
> Aeration and turbulence causes the dissolved gases in the water to
> equalize with the atmosphere at the contact points (water's surface and
> surface area of any bubbles pushed through). If a relatively air-tight
> cover were installed above a tank, then CO2 could be pumped into the
> cover (ie: from a pressurised CO2 tank), effectively making the cover an
> environmental chamber. If the air pump's intakes (or the air pumps
> themselves) were also in this 'chamber', you could have as much bubbles
> as you liked (without any negative effects on CO2 levels, actually it
> would have a net positive effect in a heavily planted tank during peak
> consumption).
>
> This design precludes the use of any open loop devices (no HOB
> powerfilters, no sump filters, no trickle filters), so filtration would
> either need to be inside (internal canisters, UGF, RUGF, sponge etc) or
> closed loop (external canisters). That's not too bad as it still leaves
> lots of options.
>
> From an air quality view, more of the CO2 would be converted into plant
> growth than escaping into the atmosphere for us to breathe as happens now
> (assuming some sealing around the chamber), so this is a positive aspect.
> Accordingly, CO2 usage and operating costs would decrease (greater
> efficiencies to achieve comparable growth).
>
> My understanding is that CO2 gas is inert (non-oxidizing), so the big
> concern would be the acidic condensation on the inside of the cover (from
> the carbonic acid).
>
> As an aside, would it be better if we used a known fixed pressurised
> CO2 - nitrogen mixture? Current commercial/industrial CO2 applications
> are for things like cooling, welding, carbonizing drinks or providing an
> inert atmosphere, so the actual mix of gases might not be ideal for
> aquatic plant growth (I'm just a wealth of good questions, but this
> newsgroup tends to be a wealth of good answers :o).
>
> One unknown potential to using an environmental chambers as an aquarium
> hood is that CO2 testers might be cheaper than pH testers, though we
> would probably still need to monitor the water's pH (unless we monitored
> the kH and CO2 levels concurrently). I haven't thought this part through
> yet, but it would be great to have a simple fool-proof way to at-a-glance
> know if your tank's pH was getting too low, so that you would dial back
> your CO2 concentration.
>
> On the down side, the aquarium cover would probably be larger (unsightly)
> and require more sealing (around electrical connections, hoses, heater
> wires and tank edge). As drawbacks, these are not huge. I've built
> custom covers out of wood which could have been upgraded to these
> requirements with some fibreglass or epoxy coating inside and some
> weather-stripping along the edge. The seal does not and should not be
> perfect as the chamber will need to replenish trace gases consumed (ergo
> my CO2+N question on the pressurised tanks).
>
> Anyways, I thought I'd percolate this by the experts ;~).

"The Complete Book of Aquarium Plants" by R. Allgayer and J. Teton, 1986
(in France) 1987 (English - Ward Lock Limited) ISBN 0-76063-6614-X
extensively discusses use of a CO2 "bell jar" at the water surface. It's
made by siliconing 5 pieces of glass into a tiny, inverted aquarium -
but I suppose you could use any inverted container and run the CO2 into
it. There's a calculation involving aquarium size, alkalinity and
desired CO2 concentration in water, that determines the size of the bell
jar.

Simpler than adding CO2 to the canopy, yet a similar idea. I still have
not tried CO2, though.

Steve

[Elaine T]

NetMax wrote:
> Has anyone heard of controlling the water's pH/CO2 level by controlling
> the CO2 concentration *above* the water surface rather than by pumping it
> through the tank's water in little bubbles?
>
> Aeration and turbulence causes the dissolved gases in the water to
> equalize with the atmosphere at the contact points (water's surface and
> surface area of any bubbles pushed through). If a relatively air-tight
> cover were installed above a tank, then CO2 could be pumped into the
> cover (ie: from a pressurised CO2 tank), effectively making the cover an
> environmental chamber. If the air pump's intakes (or the air pumps
> themselves) were also in this 'chamber', you could have as much bubbles
> as you liked (without any negative effects on CO2 levels, actually it
> would have a net positive effect in a heavily planted tank during peak
> consumption).
>
> This design precludes the use of any open loop devices (no HOB
> powerfilters, no sump filters, no trickle filters), so filtration would
> either need to be inside (internal canisters, UGF, RUGF, sponge etc) or
> closed loop (external canisters). That's not too bad as it still leaves
> lots of options.
>
> From an air quality view, more of the CO2 would be converted into plant
> growth than escaping into the atmosphere for us to breathe as happens now
> (assuming some sealing around the chamber), so this is a positive aspect.
> Accordingly, CO2 usage and operating costs would decrease (greater
> efficiencies to achieve comparable growth).
>
> My understanding is that CO2 gas is inert (non-oxidizing), so the big
> concern would be the acidic condensation on the inside of the cover (from
> the carbonic acid).
>
> As an aside, would it be better if we used a known fixed pressurised
> CO2 - nitrogen mixture? Current commercial/industrial CO2 applications
> are for things like cooling, welding, carbonizing drinks or providing an
> inert atmosphere, so the actual mix of gases might not be ideal for
> aquatic plant growth (I'm just a wealth of good questions, but this
> newsgroup tends to be a wealth of good answers :o).
>
> One unknown potential to using an environmental chambers as an aquarium
> hood is that CO2 testers might be cheaper than pH testers, though we
> would probably still need to monitor the water's pH (unless we monitored
> the kH and CO2 levels concurrently). I haven't thought this part through
> yet, but it would be great to have a simple fool-proof way to at-a-glance
> know if your tank's pH was getting too low, so that you would dial back
> your CO2 concentration.
>
> On the down side, the aquarium cover would probably be larger (unsightly)
> and require more sealing (around electrical connections, hoses, heater
> wires and tank edge). As drawbacks, these are not huge. I've built
> custom covers out of wood which could have been upgraded to these
> requirements with some fibreglass or epoxy coating inside and some
> weather-stripping along the edge. The seal does not and should not be
> perfect as the chamber will need to replenish trace gases consumed (ergo
> my CO2+N question on the pressurised tanks).
>
> Anyways, I thought I'd percolate this by the experts ;~).

This is done in tissue culture incubators to control the pH of the
culture media. CO2 is monitored, and there is also a pH indicator dye
in the culture media. However, you need to provide fresh air for O2 as
well as C02, at least at night when the plants aren't pearling. The gas
mix that's used for incubators is a sterile mixture of 95% air, and only
5% CO2. The tissue culture cells are kept in shallow media so that gas
exchange is good. Since your application is not sterile, rather than
the bulky 5% CO2 tanks, you would want your hood design to inject fresh
air along with a small amount of CO2. Or, design it to be opened at
night and closed during the day...that doesn't fit your love of
automation, though. ;-)

--
Elaine T __
http://eethomp.com/fish.html <'__><
rec.aquaria.* FAQ http://faq.thekrib.com

[NetMax]

"Elaine T" > wrote in message
. com...
> NetMax wrote:
>> Has anyone heard of controlling the water's pH/CO2 level by
>> controlling the CO2 concentration *above* the water surface rather
>> than by pumping it through the tank's water in little bubbles?
>>
>> Aeration and turbulence causes the dissolved gases in the water to
>> equalize with the atmosphere at the contact points (water's surface
>> and surface area of any bubbles pushed through). If a relatively
>> air-tight cover were installed above a tank, then CO2 could be pumped
>> into the cover (ie: from a pressurised CO2 tank), effectively making
>> the cover an environmental chamber. If the air pump's intakes (or the
>> air pumps themselves) were also in this 'chamber', you could have as
>> much bubbles as you liked (without any negative effects on CO2 levels,
>> actually it would have a net positive effect in a heavily planted tank
>> during peak consumption).
>>
>> This design precludes the use of any open loop devices (no HOB
>> powerfilters, no sump filters, no trickle filters), so filtration
>> would either need to be inside (internal canisters, UGF, RUGF, sponge
>> etc) or closed loop (external canisters). That's not too bad as it
>> still leaves lots of options.
>>
>> From an air quality view, more of the CO2 would be converted into
>> plant growth than escaping into the atmosphere for us to breathe as
>> happens now (assuming some sealing around the chamber), so this is a
>> positive aspect. Accordingly, CO2 usage and operating costs would
>> decrease (greater efficiencies to achieve comparable growth).
>>
>> My understanding is that CO2 gas is inert (non-oxidizing), so the big
>> concern would be the acidic condensation on the inside of the cover
>> (from the carbonic acid).
>>
>> As an aside, would it be better if we used a known fixed pressurised
>> CO2 - nitrogen mixture? Current commercial/industrial CO2
>> applications are for things like cooling, welding, carbonizing drinks
>> or providing an inert atmosphere, so the actual mix of gases might not
>> be ideal for aquatic plant growth (I'm just a wealth of good
>> questions, but this newsgroup tends to be a wealth of good answers
>> :o).
>>
>> One unknown potential to using an environmental chambers as an
>> aquarium hood is that CO2 testers might be cheaper than pH testers,
>> though we would probably still need to monitor the water's pH (unless
>> we monitored the kH and CO2 levels concurrently). I haven't thought
>> this part through yet, but it would be great to have a simple
>> fool-proof way to at-a-glance know if your tank's pH was getting too
>> low, so that you would dial back your CO2 concentration.
>>
>> On the down side, the aquarium cover would probably be larger
>> (unsightly) and require more sealing (around electrical connections,
>> hoses, heater wires and tank edge). As drawbacks, these are not huge.
>> I've built custom covers out of wood which could have been upgraded to
>> these requirements with some fibreglass or epoxy coating inside and
>> some weather-stripping along the edge. The seal does not and should
>> not be perfect as the chamber will need to replenish trace gases
>> consumed (ergo my CO2+N question on the pressurised tanks).
>>
>> Anyways, I thought I'd percolate this by the experts ;~).
>
> This is done in tissue culture incubators to control the pH of the
> culture media. CO2 is monitored, and there is also a pH indicator dye
> in the culture media. However, you need to provide fresh air for O2 as
> well as C02, at least at night when the plants aren't pearling. The
> gas mix that's used for incubators is a sterile mixture of 95% air, and
> only 5% CO2. The tissue culture cells are kept in shallow media so
> that gas exchange is good. Since your application is not sterile,
> rather than the bulky 5% CO2 tanks, you would want your hood design to
> inject fresh air along with a small amount of CO2. Or, design it to be
> opened at night and closed during the day...that doesn't fit your love
> of automation, though. ;-)
>
> --
> Elaine T

lol, cyclical operations such as the daily opening and closing of an air
damper is what automation does best :o). A night-time purge might be all
that is needed to replenish the system's O2 and trace gas requirements.
Steve's bell idea was quite interesting too, possibly to make a hybrid
design using the water as the seal, and leaving the rest of the aquarium
open (small gap along the front for feeding and weekly maintenance
through a typical louver. From the feedback so far, my inclination is to
still pursue the concept of a canopy chamber.
--
www.NetMax.tk

[Daniel Morrow]

Bottom posted.


"NetMax" > wrote in message
.. .
> Has anyone heard of controlling the water's pH/CO2 level by controlling
> the CO2 concentration *above* the water surface rather than by pumping it
> through the tank's water in little bubbles?
>
> Aeration and turbulence causes the dissolved gases in the water to
> equalize with the atmosphere at the contact points (water's surface and
> surface area of any bubbles pushed through). If a relatively air-tight
> cover were installed above a tank, then CO2 could be pumped into the
> cover (ie: from a pressurised CO2 tank), effectively making the cover an
> environmental chamber. If the air pump's intakes (or the air pumps
> themselves) were also in this 'chamber', you could have as much bubbles
> as you liked (without any negative effects on CO2 levels, actually it
> would have a net positive effect in a heavily planted tank during peak
> consumption).
>
> This design precludes the use of any open loop devices (no HOB
> powerfilters, no sump filters, no trickle filters), so filtration would
> either need to be inside (internal canisters, UGF, RUGF, sponge etc) or
> closed loop (external canisters). That's not too bad as it still leaves
> lots of options.
>
> From an air quality view, more of the CO2 would be converted into plant
> growth than escaping into the atmosphere for us to breathe as happens now
> (assuming some sealing around the chamber), so this is a positive aspect.
> Accordingly, CO2 usage and operating costs would decrease (greater
> efficiencies to achieve comparable growth).
>
> My understanding is that CO2 gas is inert (non-oxidizing), so the big
> concern would be the acidic condensation on the inside of the cover (from
> the carbonic acid).
>
> As an aside, would it be better if we used a known fixed pressurised
> CO2 - nitrogen mixture? Current commercial/industrial CO2 applications
> are for things like cooling, welding, carbonizing drinks or providing an
> inert atmosphere, so the actual mix of gases might not be ideal for
> aquatic plant growth (I'm just a wealth of good questions, but this
> newsgroup tends to be a wealth of good answers :o).
>
> One unknown potential to using an environmental chambers as an aquarium
> hood is that CO2 testers might be cheaper than pH testers, though we
> would probably still need to monitor the water's pH (unless we monitored
> the kH and CO2 levels concurrently). I haven't thought this part through
> yet, but it would be great to have a simple fool-proof way to at-a-glance
> know if your tank's pH was getting too low, so that you would dial back
> your CO2 concentration.
>
> On the down side, the aquarium cover would probably be larger (unsightly)
> and require more sealing (around electrical connections, hoses, heater
> wires and tank edge). As drawbacks, these are not huge. I've built
> custom covers out of wood which could have been upgraded to these
> requirements with some fibreglass or epoxy coating inside and some
> weather-stripping along the edge. The seal does not and should not be
> perfect as the chamber will need to replenish trace gases consumed (ergo
> my CO2+N question on the pressurised tanks).
>
> Anyways, I thought I'd percolate this by the experts ;~).
> --
> www.NetMax.tk
>
>

Sounds like a wonderful idea, much like a macgyver idea. :-D I'd love to try
it after you work it out, even if it ultimately would be a custom job as
opposed to a commercial product, after all - most co2 projects/set ups are
custom anyways and your idea is NOT too hard at all. Good luck and later!

[Nikki Casali]

NetMax wrote:


> Anyways, I thought I'd percolate this by the experts ;~).

Ehmmmm. What CO2 concentration could one expect with this setup?

Nikki

[NetMax]

"Nikki Casali" > wrote in message
...
> NetMax wrote:
>
>
>> Anyways, I thought I'd percolate this by the experts ;~).
>
> Ehmmmm. What CO2 concentration could one expect with this setup?
>
> Nikki


I'm really hoping an expert will jump in to properly answer this... help
(Michi!).

At 20C, equalization points for CO2 are, (I think) 375ppm atmospheric (or
0.0314%) and 2-3ppm aquatic (0.15%). Does that help?
--
www.NetMax.tk

[Nikki Casali]

NetMax wrote:
> "Nikki Casali" > wrote in message
> ...
>
>>NetMax wrote:
>>
>>
>>
>>>Anyways, I thought I'd percolate this by the experts ;~).
>>
>>Ehmmmm. What CO2 concentration could one expect with this setup?
>>
>>Nikki
>
>
>
> I'm really hoping an expert will jump in to properly answer this... help
> (Michi!).
>
> At 20C, equalization points for CO2 are, (I think) 375ppm atmospheric (or
> 0.0314%) and 2-3ppm aquatic (0.15%). Does that help?

So I'd need 3750ppm in the chamber for 25ppm? I bet it's not so linear.
The only way to know is for someone to set up a test tank. I wonder what
the fish will think when they race up to the surface for a gulp of nice
oxygenated (fizzy!) air?

Nikki

[NetMax]

"Nikki Casali" > wrote in message
...
> NetMax wrote:
>> "Nikki Casali" > wrote in message
>> ...
>>
>>>NetMax wrote:
>>>
>>>
>>>
>>>>Anyways, I thought I'd percolate this by the experts ;~).
>>>
>>>Ehmmmm. What CO2 concentration could one expect with this setup?
>>>
>>>Nikki
>>
>>
>>
>> I'm really hoping an expert will jump in to properly answer this... help
>> (Michi!).
>>
>> At 20C, equalization points for CO2 are, (I think) 375ppm atmospheric (or
>> 0.0314%) and 2-3ppm aquatic (0.15%). Does that help?
>
> So I'd need 3750ppm in the chamber for 25ppm? I bet it's not so linear.
> The only way to know is for someone to set up a test tank. I wonder what
> the fish will think when they race up to the surface for a gulp of nice
> oxygenated (fizzy!) air?
>
> Nikki


Interesting point. Catfish and labyrinths might have something to say about
that, though I don't think the CO2 levels would really need to be quite that
high. Underwater, CO2 will not crowd out O2 in normal circumstances (most
anything we would want for a live aquatic application), however I don't know
how that principle applies, especially when dealing with a labyrinth organ,
or the intestinal lining of a catfish. CO2 is commonly used in various
factory processing applications, and I don't recall any particular health
advisories (other than injury to skin from the cold ;~), but I'm sure it has
bad effects when taken to some degree (or extreme?).

However, I picture environments where there was high CO2 in the air (swamps,
jungles) as being exactly the kind of places where air-breathing fish had
evolved (jungles of Thailand & Brazil), so perhaps the application will
still be sound at the CO2 levels we would target.
--
www.NetMax.tk