CO2 Does Not Alter KH - The Planted Tank Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 35 (permalink) Old 09-30-2014, 08:03 PM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile CO2 Does Not Alter KH

Hi

I was not going to do this for a while but the whole Lowering KH thing stirred the questions.

Guru warning, I know this is contrary to some dearly held Guru Views, as well as cut-‘n-paste-Google experts;

  • cut-‘n-paste-Google-experts ought to be ashamed.
On matter of religious belief, if a Rabbi, Priest, Guru, Muftis, Preacher, Minister, Clergy person, religious leader tells you differently and you are a true believer accept what they say, I will not argue.
I realize sitting at my keyboard how dis-consoling it could be to think I am sitting on

  • a rock spinning at 890-mph ((1070-mph X cos (your latitude) for approximate speed),
  • traveling around a star, itself moving at 67,000-mph, which, is part of
  • a galaxy hurtling at 1,300,000-mph through the universe, on a collision course with another galaxy.
Oh my, that is disquieting…
  • Almost as disquieting as imagining CO2 does not affect KH.

Under aquarium conditions and reasonable rates, adding (injecting more) or subtracting (injecting less) Carbon dioxide (CO2) will not change the bicarbonate/carbonate (KH) level. For the purposes of this thread we will assume the temperatures at 25C (77F).

The first clue (my opinion) are the names Carbon dioxide and carbonate. Oh well, I am simple soul and not particularly bright. Words amuse me and sometimes provide hints, sometimes even speak to me (!?).

The second part is a bit more confusing. As we inject CO2 as a gas (for these purposes we will assume essentially injecting soda water as I do) we understand (accept) that only a small percentage of CO2 becomes carbonic acid the vast majority remains (or is) solvated. For the most part any visible bubbles are not participating in any reaction and are essentially wasted CO2.


Respectfully,
Joe
FBTB

If your Guru tells you otherwise and you are true believer that is okay I will not argue the point.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I pretty much limit what I say to things that anyone can easily verify from recognized references or by direct observation. If it is my opinion I say so.

JoeRoun is offline  
Sponsored Links
Advertisement
 
post #2 of 35 (permalink) Old 09-30-2014, 08:53 PM
Wannabe Guru
 
PTrader: (6/100%)
Join Date: Aug 2011
Location: Centennial,Co
Posts: 1,836
Great, warn the gurus and then proceed to talk about solvation!
BruceF is offline  
post #3 of 35 (permalink) Old 09-30-2014, 09:39 PM
Planted Tank Guru
 
plantbrain's Avatar
 
PTrader: (267/100%)
Join Date: Dec 2003
Location: The swamp
Posts: 13,609
+1


Only 1 out 400 of those CO2 ends up as H2CO3, the remainder ........as dissolved CO2[aq] gas. Much like O2 etc that also is dissolved into water, but does not react.

Folks can add all the CO2 they wish and then measure the KH before and after, did it change? Nope. Happens daily, but the KH does not change.


Add aectic acid, vinegar, it'll change and remove the KH, add HCL, it'll do the same thing. Not CO2.

Bump:
Quote:
Originally Posted by BruceF View Post
Great, warn the gurus and then proceed to talk about solvation!
Solvation or salvation?




Regards,
Tom Barr
plantbrain is offline  
 
post #4 of 35 (permalink) Old 09-30-2014, 09:43 PM
Planted Tank Guru
 
PTrader: (3/100%)
Join Date: Aug 2014
Location: Maryland, USA
Posts: 2,340
Edit: nevermind, you originally linked just your own post, and I was trying to figure out how *that* was suggesting CO2 could alter KH.

(ie: I thought you were counter-arguing your own post)

Last edited by mattinmd; 09-30-2014 at 09:58 PM. Reason: retracted as I mis-read
mattinmd is offline  
post #5 of 35 (permalink) Old 09-30-2014, 11:06 PM
Children Boogie
 
mistergreen's Avatar
 
PTrader: (13/100%)
Join Date: Dec 2006
Location: Cincinnati
Posts: 16,743
I thought folks who are familiar with CO2 know this?
That's how a drop checker works. kH stays while pH changes.
mistergreen is offline  
post #6 of 35 (permalink) Old 10-01-2014, 12:17 AM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile A Bit O Fun W/ A Serious Side

Hi,

The Lowering KH via Lime & Muriatic Acid is itself an answer to something in other threads as well as privately submitted questions.

I seem to offend Gurus, I do not mean to, but I do. I intend to offend the “cut-‘n-paste-experts” along with those that cite research they have not read; they are a blight.

As part of my policy not to argue with the anointed or offend any religious sensibilities I will simply state that I have been informed that CO2 reduces KH. I am not picking a fight, proxy or otherwise.

In several of the discussions about KH, there have been questions and answers that suggested carbonic acid reduces KH.

I did not care to deviate from the discussion, I decided it better to make specific points of fact in separate threads so as not to side track another discussion.
I have a series of these, some requested, some folks have been asking me over the last couple of years, some based on what I have seen here and in other forums.

The main thing; it is kind of fun to take on issues that some seem to take as a matter of opinion.


Most of what I say is easily verifiable fact and/or can easily be observed.
  • The CRC Handbook of Chemistry and Physics, The Merck Veterinary Manual, Tom Barr’s pre-June 2009 missives and a number of textbooks from classes taken over the last few years are my primary resources, though when citing something I try internet links.

So what I say is not meant to be a revelation, an opportunity to lay it out and if there are questions, perhaps we can explain or figure it out together.

None of what I say is original, I am not particularly bright. I am persistent and inquisitive, and always wanting to learn. I try not to plagiarize anybody, but sometimes in running off the cuff stuff, well…

I think one of the most interesting answers I receive (and yes I have received it here) is “just Google it and see all of the posts…” or “that’s what everyone says…”

Hopefully it is a friendly mocking of the “experts.”

I am old enough to know how many things I was taught and thought were true that we now laugh about…

Respectfully,
Joe
FBTB

If your Guru tells you otherwise and you are true believer that is okay I will not argue the point.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I pretty much limit what I say to things that anyone can easily verify from recognized references or by direct observation. If it is my opinion I say so.


Last edited by JoeRoun; 10-01-2014 at 12:20 AM. Reason: complete sentence
JoeRoun is offline  
post #7 of 35 (permalink) Old 10-01-2014, 12:21 AM
Wannabe Guru
 
greaser84's Avatar
 
PTrader: (11/100%)
Join Date: Feb 2014
Location: NC
Posts: 1,425
Quote:
Originally Posted by JoeRoun View Post
Hi


Guru warning, I know this is contrary to some dearly held Guru Views
I don't know any Guru's that think CO2 will alter KH...


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
greaser84 is offline  
post #8 of 35 (permalink) Old 10-01-2014, 12:25 AM
Planted Tank Guru
 
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,015
Hoppy is offline  
post #9 of 35 (permalink) Old 10-01-2014, 12:54 AM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile Close Maybe... No Misrepresentation...

Quote:
Originally Posted by Hoppy View Post
Hi Hoppy,

No I do not think there is any misrepresentation of fact (intentions perhaps). I am trying to separate some of these things.

What has bothered me the most is seeing the confusion on the part of some honestly curious folk, slammed shut… By absolutist comments that were not supportable.


I actually think the problem lies with confusion about pH, KH, GH and which rules are in play at a given time, why I intend to address them individually without pointing my finger at anyone in particular while going after the cut-’n-pasters and maybe a little fun at the expense of Gurus.

Respectfully,
Joe
FBTB

If your Guru tells you otherwise and you are true believer that is okay I will not argue the point.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I pretty much limit what I say to things that anyone can easily verify from recognized references or by direct observation. If it is my opinion I say so.

JoeRoun is offline  
post #10 of 35 (permalink) Old 10-01-2014, 03:45 AM
Planted Tank Guru
 
PTrader: (3/100%)
Join Date: Aug 2014
Location: Maryland, USA
Posts: 2,340
Carbonic acid reducing KH? Wow, that's pretty laughable, even from my very non-expert point of view and "it's been 20 years since I took CHEM 112" perspective.

The hydrogen carbonic acid could in theory react with existing carbonate, just as any acid could. But in doing so would leave its own carbonate behind. Take a carbon, leave a carbon, net change 0. This action clearly can't reduce KH.

If anything I would expect CO2 injection creating Carbonic acid to trivially *increase* KH, at least temporarily. Carbonic acid does create more carbonate ions in solution.

Of course, our concentrations a pretty small, 30ppm CO2, resulting in something less than 0.1ppm Carbonic acid, and less than that in carbonate. So, maybe 1/300'th of a German degree? (Assuming there's not too much rounding errors in my rough swags).


Did I get that correct? (roughly speaking?)
mattinmd is offline  
post #11 of 35 (permalink) Old 10-01-2014, 07:27 AM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile I Come Offering Solvation...

Hi

Yes, roughly correct, though I think your figures are way on the high side. See Plantbrain’s post.

Now try some arithmetic and relationship to pH and KH and we are well on our way.

One of the problems, things to explain is the Ka, or rather Ka’s. The other point of confusion is how is it an acid, how does it reduce pH so much and not change KH. After all if Plantbrain is correct that hypothetical 30-ppm of CO2 is only yielding 75-ppb H2CO3, yet that can translate into a full pH degree drop for the solution.

It really isn’t complicated though it is confusing and I think some “experts” either use that to confuse or are confused themselves.

Respectfully,
Joe
FBTB

If your Guru tells you otherwise and you are true believer that is okay I will not argue the point.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I pretty much limit what I say to things that anyone can easily verify from recognized references or by direct observation. If it is my opinion I say so.


Last edited by JoeRoun; 10-01-2014 at 07:29 AM. Reason: that in wrong place
JoeRoun is offline  
post #12 of 35 (permalink) Old 10-01-2014, 09:05 AM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile Henderson was fine but the Hassle of Hasselbalch

Hi

Kind of a starting point for the arithmetic.



The formula most of us are familiar with, the fine Dupla people made famous (yes, I was a Dupla dope).
  • CO2= 3 X dKH X 10^(7-pH).
  • What does it mean?
  • What does it tell us?
  • What are those numbers?
  • Where did it come from (hint Dupla only made it famous for aquarists).
Should you want it in ppm CO2 = 3 X (dKH X 0.056) X 10^(7-pH). M

As Zorfox has pointed out I erred in stating this was to get CO2 in ppm, obviously it does not.
Apologies! I should not have mentioned it, I confused myself.
The 0.056 factor would only be used if the KH were given in ppm, hence the reason Zorfox got such different answers.

Joe, FBTB, 10-01-2014

Respectfully,
Joe
FBTB

Last edited by JoeRoun; 10-01-2014 at 09:59 PM. Reason: My Goof As Exposed by Zorfox
JoeRoun is offline  
post #13 of 35 (permalink) Old 10-01-2014, 02:27 PM
Planted Tank Guru
 
PTrader: (3/100%)
Join Date: Aug 2014
Location: Maryland, USA
Posts: 2,340
Quote:
Originally Posted by JoeRoun View Post
Hi

Yes, roughly correct, though I think your figures are way on the high side. See Plantbrain’s post.
Fair enough, they were intended to be a very rough swag, with a lot of rounding towards the high-side. Hence the "maybe" in the "maybe 1/300'th of a German degree"... I guess I should have bolded that maybe to emphasize that it is a bit on the incredulous side.
mattinmd is offline  
post #14 of 35 (permalink) Old 10-01-2014, 04:32 PM
Planted Tank Guru
 
Zorfox's Avatar
 
PTrader: (5/100%)
Join Date: Jun 2012
Location: Gainesville, FL
Posts: 2,105
Quote:
Originally Posted by JoeRoun View Post
  • CO2= 3 X dKH X 10^(7-pH).
Actually, I think this formula is a little more accurate
CO2 = 12.839 * dKH * 10^(6.37 - pH)


Quote:
Originally Posted by JoeRoun View Post
Should you want it in ppm CO2 = 3 X (dKH X 0.056) X 10^(7-pH).
As far as I know the formula above already reports the CO2 as parts per million.

Here is a nice post describing the calculation.
Zorfox is offline  
post #15 of 35 (permalink) Old 10-01-2014, 05:53 PM Thread Starter
Planted Tank Enthusiast
 
JoeRoun's Avatar
 
PTrader: (0/0%)
Join Date: Dec 2009
Location: Surprise, AZ
Posts: 634
Smile The Optimum Aquarium, Horst & Kipper

Hi Zorfox,

Okay 12.839 * dKH * 10^(6.37 - pH) is a manipulation of the same equation, where George Booth set dKH equal to 17.8-ppm, rather than 17.85 and did the conversion at the molar value to ppm.

Actually I remember this “discussion.” I am not sure that it is has a greater accuracy, it is perhaps a bit more direct, maybe it makes it easier to follow back and answer my above questions.

I suspect this equation and chart as much of Horst and Kipper’s endeavors were marketing based, there is no doubt in my mind that the modern planted tank world is very much there construction.

The CO2, pH, KH charts you see about are based on the “Dupla” equation, setting dKH equal to 17.85-ppm, the 0.056 is simply a conversion from dKH to ppm.

Thanks Zorfox, good addition, but on with the arithmetic, what does it all mean, either equation.

Respectfully,
Joe
FBTB

If your Guru tells you otherwise and you are true believer that is okay I will not argue the point.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I pretty much limit what I say to things that anyone can easily verify from recognized references or by direct observation. If it is my opinion I say so.

JoeRoun is offline  
Reply

Tags
carbonate hardness, carbonic acid, co2, ph-kh

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome