Re: [AGA Member] CO2 efficiency in hard water

["S. Hieber" <shieber@yahoo.com>]

--- Amit Brucker <amitb@gtek.co.il> wrote:
> Scott,
> Thanks for the answears.
> Let me make myself clear a bit more,
> If I'll take out my CO2 system - I am not sure it will
> effect the plants
> much.

If you take out hte CO2 system, will be be allowing your
plants only the CO2 that's normally inthe water, just f few
ppm or what they can get when they reach the water surface,
where the level of CO2 is measured in hundreds.

> Assuming that my PH/KH are stable at all times - this
> means I'll have stable
> amounts of dissolved CO2 ?

If you took away the CO2 injection and you pH did not rise
after a few days, I would take this to mean that you were
not getting any CO2 into the water with your CO2 system
*AND* you were lowering the pH by some other acid. I don't
think you can have a KH of 12 and  pH of 7.2 without some
acid being present.

> Is this also may be the reason for not seeing to much CO2
> diffusion in the
> water ???

I'm not sure what you're looking for. If you want 100% of
the CO2 to dissolve into the water, get or make an external
reactor. There are some simple inexpensive plans around for
DIY. The ready-made reactors tend to be very pricey.  With
an external reactor you'll get 100% absortion of the CO2
into the water.

> Sure I know that CO2 is one of the three important
> nutrient, but my tap
> water seems to have fair amount of it considering
> KH&KH....

Even if your tap water has CO2, water doesn't hold onto CO2
very well. You have to contiually add it since it
continually escapes.

> So it seem to my that my system does not contribute too
> much for my tank.
> Now ask this: Ok, stop using the CO2 system. Lets
> consider plants taking up
> all CO2 in the water, what then ?
> 1. I don't think this should have any effect on PH and
> not I don't think PH
> levels would rise.

Why not. You remove an acid from the water andthe pH will
rise unless your tank was buffered to the point that you
had carbonate precipitates. Then removing the acid would
jsut mean more of the precipitate would dissolve -- but for
Caclium carbonate, for example to precipitate, you'd need
the pH to be way up past.

> 2. The tank is aerated during the night - I  guess that
> some CO2 enters the
> tank as well.

More likely, it drives off watever is in there down to the
normal levels in water of just a few ppm.

So now you take all day to try to build up the levels
again, only to literally blow them out of hte water each
night.

I'd like to know if any other acids are in the water. Are
you adding any buffers. Organics aren't a source unless you
go long period without water changes and have lots of
detrituts inthe tank. 

Stop the nightly aeration -- rely on your plants for
oxygenating the water during the day. After staturation,
the levels will be fine all night.

Do 50% weekly water changes to reduce the impact on any
organic.

Raise the CO2 level to get up to 30 ppm just to see if you
can lower pH by doing so.

sh

=====
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