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[APD] Re:pH and CO2 questions

Here are my final coments on this issue =)
A. regardless of the reletive amount of CO2 as free C02 or as H2CO3
(carbonic acid) the ratio of the two remains the same, therefore we can
equate CO2 and H2CO3 for the purposes of the henderson-hasselbach
equation aka for calculating the equillibrium btw. C02 and HCO3-

B. I aggree with Andrew. just substitue "free CO2" for "carbonic acid"
(because of point A above) therefore at a low KH/pH more of the CO2 you
inject will be free CO2 because less will be converted to bicarbonate. 

basically every molecule of CO2 that is used to reduce the pH is
wasted/converted to bicarbonate.
If your water has a low KH and is already at, for example, pH 6.35 most
of the CO2 you inject will remain as free CO2  (because of the
equillibrium point btw CO2 and HCO3- is pH 6.35). 

If you start with a pH of 7.5 and aim to reduce it to pH6.8, all the
Hydrogens used to drop the pH from 7.5 to 6.8 came from "wasted" CO2

So If you are concerned about every molecule of CO you input into the
system (which is not the case if you use a CO2 tank) a lower KH will

Feel free to correct me at will, I am not an expert on this matter by
any means, but this should be true according to my basic understanding
of buffering systems. I could elaborate on all the above points, but I
don't think that anyone really cares that much =). 

Tarah Nyberg
in crisp but not cold Dallas...*sigh*

Unless I misread Paul Sears Article in TAG a few issues
ago, only about one part in 2000 of CO2 goes to carbonic

Scott H.
--- Andrew McLeod <thefish at theabyssalplain_freeserve.co.uk>

> I didn't think the level of carbonates affected pH, which
> depends only on 
> H+ ions.
> Wouldn't decreasing the KH reduce the amount of carbonic
> acid absorbed 
> into hydrogen carbonates to form bicarbonates? Thereby
> increasing the 
> fraction of CO2 left dissolved as carbonic acid and so
> available to the 
> plants?

S. Hieber

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Message: 9
Date: Fri, 5 Dec 2003 18:14:07 EST
From: Dgrim62 at cs_com 
Subject: [APD] Re: how much light
To: aquatic-plants at actwin_com 

Thanks for the substrate/water example George. I guess I should have
that water in the substrate is similar to water in the sump, not part
of the 
water volume in the tank that is being lit, and therefore doesn't have
a part in 
calculating true watts per gallon.

Sounds better to me! :-)



Message: 10
Date: Fri, 5 Dec 2003 17:17:41 -0600
From: "Steven Pituch" <spituch at ev1_net>
Subject: [APD] Re: Refreshing old substrate (repost)
To: <aquatic-plants at actwin_com>

You could do a  "roll your own cigarettes ala Walstad".

Get some garden soil, and wax paper.  Put some of the soil on a piece
of wax
paper.  Roll up the waxpaper into a tube and scotch tape it closed. 
the soil cigarette deep into the substrate.  Do this all over the
Gradually, the paper will disolve.  If you want to speed up the process
a knife and stab the substrate where you pushed in the cigarettes. 
will break open the wax paper tubes.
This is all detailed in her book "Ecology of the Planted Aquarium".

Steve P.


Message: 11
Date: Fri, 5 Dec 2003 15:15:17 -0800 (PST)
From: "S. Hieber" <shieber at yahoo_com>
Subject: Re: [APD] Re: how much light?
To: aquatic plants digest <aquatic-plants at actwin_com>

If we're accepting that light comes back from the sides of
the tank, then front-to-back depth must matter too on where
the light is "focused."  No?

Scott H.
--- Andrew McLeod <thefish at theabyssalplain_freeserve.co.uk>
> As to the 2-3 wpg rule, I once saw an interesting site
> about a more 
> mathematical approach to this.
> As with all approximations, I would assume it tended to
> break down at 
> extremes. 240 gallons would be an extreme, surely?
> But then again, if height is not that important, then all
> that matters is 
> that you have enough light for your plants - and plants
> take up volume, 
> not length.
> -- 
> Andrew McLeod
> thefish at theabyssalplain_freeserve.co.uk 
> _______________________________________________
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com 
> http://www.actwin.com/mailman/listinfo.cgi/aquatic-plants 

S. Hieber

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Message: 12
Date: Fri, 5 Dec 2003 15:16:33 -0800 (PST)
From: "S. Hieber" <shieber at yahoo_com>
Subject: Re: [APD] marine topics
To: aquatic plants digest <aquatic-plants at actwin_com>

APD won't let you post them here, but if you post them
somewhere, please let us know.

Scott H.
--- Christopher Hind <cixcell at yahoo_com> wrote:
> --- "S. Hieber" <shieber at yahoo_com> wrote:
> > See? We'd do okay here talking about it seaweed. ;-)
> i wish i had a digital camera that did macro so i
> could do some closeups of the species ive collected
> and am currently propagating. maybe ill try using my
> webcam.

S. Hieber

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Message: 13
Date: Fri, 05 Dec 2003 20:15:14 -0500
From: Bill Wichers <billw at waveform_net>
Subject: [APD] Re: glowfish banned
To: aquatic-plants at actwin_com 

>Of course, properly kept, there is little to no risk of contamination.
>is only when some stupid lazy person gets bored of their fish/plants
>flushes them alive, or otherwise allows this contamination, that
>escape. It makes no

I would be very surprised to see *any* fish survive a trip through the

sewer system. Even if the fish could survive the very, very hostile 
environment in the piping (black water in sewer lines is _not_ good for

anything besides some strains of bacteria), the treatment plant at the
would finish it off. In order for a fish to be released into a wild 
population it would need to be placed in a stream, lake, pond, or other

natural waterway, which unfortunately does happen occasionally.

>  difference whether the zebrafish glows or not, it could still damage

> natural ecosystems, but I assume you don't go throwing fish into
> The company states that the modified zebrafish tolerate cold less
> the unmodified fish, so since as far as I am aware zebrafish have not

> invaded the wild, then the modified version is even less likely to,
> its current known tolerances.

Seems to me that the glowing part of the fish would make it easy for 
predators to spot and thus would keep their populations down should
they be 

>engineered bioweapon (did you know the US spends more on its military
>the next twelve biggest spenders combined?),

This is irrelevant to the discussion and the implication is false.

>unfortunately the root of the problem is that humans are, as a mass, 
>stupid. Nobody would release an organism intentionally that would
>damage, yet stupidity allows it to happen anyway. Stupidity can be 
>overcome, though.

Stupidity is unfortunately extremely difficult to overcome. Even at
work we 
see problems still with users and email worms, despite repeated 
instruction, mass media attention, and even some firings of repeat 
offenders. And following the "don't open email attachments" rule is not

difficult. I think what you're talking about here is the real problem,
not one that can be easily overcome.

>Perhaps it would be prudent to place security measures in every
>Suicide genes, that inhibit wide-spread growth (the organism produces
>chemical that kills it if to much grows). In Jurassic Park, the
>were incapable of producing the amino acid lysine. By not feeding this
>the dinosaurs diet, the dinosaurs should have died, although (as in
>Lost \world), it is possible they could have eaten food high in this
>acid to survive. If rabbits were created with such a deficiency, they

>would soon breed with other rabbits and gain the proteins to do it. 
>However, dinosaurs are unlikely to breed in the wild. Perhaps all 
>organisms created should:
>a) be extinct or otherwise completely unable to breed with any other
>of life (not sterilisation, which is never 100%)
>b) be fitted with multiple suicide genes to avoid becoming a major 
>invasive problem in the event of release
>c) have huge gaps in their metabolism, making them utterly dependent
>humans to survive, and highly unlikely to gain the necessary

Now you're looking at a serious amount of work, and something that
not even be possible today. Sterilization can be 100% but such methods
likely to reduce the life span of the fish.

BTW, movies are a notoriously bad source of scientific knowledge.


Waveform Technology
UNIX Systems Administrator


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