Aquarium & Tropical Fish Site

This repository is for research only. New discussions take place in our current Tropical Fish Forum.

Archivarium 2004
Repository of our 2003/2004 Topics
 
  HelpHelp   Search BoardSearch Board   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   Check your private messagesCheck your private messages   Log inLog in   RegisterRegister 
CO2 level
 Forum Index > Plants and Planted Tanks  Search Board
View previous topic :: View next topic  
Author Message
Magnus
Advisors


Joined: 16 May 2003
Location: Cali

PostPosted: 2003.09.19(Fri)19:27    Post subject: CO2 level Reply with quote

I've been thinking about this issue and I just needed someone to confirm it (or explain it in detail, chemically?). Adding CO2 decreases pH and increases CO2 level in the water (duh). But when plants "use" CO2, the CO2 level drops and the pH rises again, correct? So the more plants I have, the faster they absorb CO2? On the other hand, the less plants I have, the slower they absorb CO2? Or does it even matter how much plants I have?
I guess what I'm trying to say is that when I had less plants, my CO2 bottle usually managed to provide a sufficient amount of CO2 for my 10g (20-30ppm). Now that my plants have grown, my CO2 bottle barely keeps the CO2 level at 10-15ppm even when I've added a new batch (I use two bottles, one replaces another as soon as the other stops producing). The more I think about this, the more confused I get (this is too dangerous for my brain Mad ).
Anyone care to confirm my theory, or explain this to me?
Thanks,
_________________
Back to top
View user's profile Send private message Visit poster's website AIM Address
William
Advisors


Joined: 06 Feb 2003
Location: Houston, Texas

PostPosted: 2003.09.19(Fri)22:04    Post subject: Re: CO2 level Reply with quote

Magnus,

This is how I understand it (Steve/Tula please correct me if I am wrong).

Magnus wrote:
I've been thinking about this issue and I just needed someone to confirm it (or explain it in detail, chemically?). Adding CO2 decreases pH and increases CO2 level in the water (duh).


This is correct injecting CO2 lowers the pH level. A by product of CO2 is carbonic acid.

Magnus wrote:
But when plants "use" CO2, the CO2 level drops and the pH rises again, correct?


It's a little more complicated than that. The CO2/carbonic acid levels are linked to the pH levels in the tank. However, fluctuations in the pH level are linked to the 24 hour cycle of the tank. Here's a simple way to look at it:

During the day, when you have your lights on, plant photosynthesis consume (respire) CO2 and produce (expire) oxygen. As the CO2 is consumed, the carbonic acid drops and the pH level increases. The peak pH level in your tank should occur at the end of the day (light cycle) in the tank.

During the night, when the lights are off, plant photosynthesis stops. Plants respire oxygen and expire CO2. The CO2 and subsequent carbonic acid produced lowers the pH level of the tank. The lowest pH level in your tank should be at the end of your night cycle.

Magnus wrote:
So the more plants I have, the faster they absorb CO2? On the other hand, the less plants I have, the slower they absorb CO2? Or does it even matter how much plants I have?I guess what I'm trying to say is that when I had less plants, my CO2 bottle usually managed to provide a sufficient amount of CO2 for my 10g (20-30ppm).


The number/amount/size of plants you have in your small tank has a direct correlation to the amount of CO2 respired and expired.

Best regards,

William
_________________
-Insert Your Favorite Quote Here-
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
 Forum Index > Plants and Planted Tanks All times are GMT - 6 Hours Search Board
Jump to:  
  You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2008 phpBB Group

oF <=> oC in <=> cm G <=> L