Re: [AGA Member] CO2 concentration in Hard water

[Erik Olson <erik@thekrib.com>]

(Of course, as I write, more mail comes through... gotta love those 
instant response lists)

> With high KH you can have a higher CO2 level and stay
> within a given pH range

Not just "can", *MUST*.  I think that's where the Red Sea info is leading
folks astray.  It makes it look like "la de da, by increasing KH you can
add more CO2 if you want..." and it should say "by increasing KH, you're
going to get a higher pH unless you add more CO2 to offset this."

I always like to go back to the chart George did 10+ years back:

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

This is a much better representation of what's actually happening than the
ones usually included in, say, _The Optimum Aquarium_ (or the one
reproduced as a table about halfway down the HTML page above) which make
it look like CO2 is the dependant variable.  You can clearly see in either
of these charts that if you want a given pH, you have to increase (or
decrease) BOTH CO2 and KH in proportion.

OK, so the other question, can plants do OK in harder or softer water:  I
know that at the soft end of the scale, eventually they can't get the
micronutrients (calcium, magnesium) supplied.  I have had this happen
once, and it wasn't pretty.  I wish I'd gotten pictures of it -- all-white
leaves.

At the other end, I dunno. I would absolutely *love* to know the answer to
this too, because it would mean that one could keep, say, Lake Tanganyika
cichlids in a beautiful planted tank (I read in Kasselmann there's about 5
species of plants there).  But I never want to risk using the high light 
and CO2 on a tanganyika tank.  Hmm, maybe time to start now.

  - Erik

-- 
Erik Olson
erik at thekrib dot com


 ------------------
 To unsubscribe from this list, please send mail to majordomo@thekrib.com
 with "Unsubscribe aga-member" in the body of the message.  Archives of
 this list can be found at http://lists.thekrib.com/aga-member/