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  • CO2 measurement

    CO2 is perhaps one of the most controversial and problematic parameters for planted aquarist. Is enrichment natural? Why add it if I've seen other tanks that do not use it still look nice and grow plants still?

    These are often folks that have not used it that ask such questions, but these questions are valid and fair.

    Can you think of systems where CO2 at say 10-40ppm is natural and stable?
    How would you measure it and also verify those levels using a known reference?
    We do this for nutrients and for light, but what about CO2?



    Regards,
    Tom Barr
    www.BarrReport.com

  • #2
    Why add it if I've seen other tanks that do not use it still look nice and grow plants still?
    Longevity of CO2 supply?

    Tom, those thanks that don't supplement CO2 (i.e. via CO2 cylinder, regulator etc), still need a CO2 source from somewhere don't they...and this CO2 source, in these cases, is coming from a specially composed substrate that slowly breaks down producing enough stable CO2 to support growth?

    Needless to say, these tanks that don't supplement CO2, would have to be very low light - with higher lighting levels this kind of result would be impossible without CO2 supplementation, correct?

    These non-supplemented tanks that look great are going to be fairly short lived aren't they? Eventually, whatever is supplying the carbon source (CO2 from substrate?), is going to run out.

    This excludes using, Excel etc, of course.
    6' Planted Tank (72" x 18" x 20") - 4 x 30W T8 Tri-Phosphors - 2 x Eheim 2217 'Classic' canisters
    Flourite substrate - Ocean Runner OR-2500 + AM1000 - Tunze Turbelle Nanostream 6045
    6.8kg Catalina CO2 - Red Sea Pro regulator - Swagelok B-SS4-A metering valve - Vecton 600 UV

    Comment


    • #3
      CO2 enrichment allows us a great deal more design freedom, or at least a more immediate level of control over design. "El natural" isn't very forgiving of indecisive design. You can't go changing things everytime you see a better way and maintain a stable environment. In some ways, and to some people, that may be too confining; others may see it as more challenging. You have to be confident of your initial design, put more forethought into it. Replace some of your freedom with patience. The maintenance end of CO2 maybe more work, but it allows you a great deal of control.

      How many natural bodies of water that support life escape evaporation/rainfall/current, moving from one place to another. Water in nature is constantly being filtered and renewed.

      Comment


      • #4
        "El natural" isn't very forgiving of indecisive design.
        I don't think CO2 enrichment is very forgiving of indecisive design either! ;-)
        6' Planted Tank (72" x 18" x 20") - 4 x 30W T8 Tri-Phosphors - 2 x Eheim 2217 'Classic' canisters
        Flourite substrate - Ocean Runner OR-2500 + AM1000 - Tunze Turbelle Nanostream 6045
        6.8kg Catalina CO2 - Red Sea Pro regulator - Swagelok B-SS4-A metering valve - Vecton 600 UV

        Comment


        • #5
          I'm not sure a direct comparison between natural systems and a tank can be made. There are not many natural streams that have high CO2. Most are very low and filled with algae, which seems logic. Aquatic plants in those streams are mostly coverd with algae too, except for the top few inches.

          We can prevent this by adding CO2. Still CO2 is a very difficult matter. There's not much too rely on. pH/KH table, drop checker, pearling, all not more then indicative. Fish? Well, we can watch the fish, but if I need 120 mg/l of CO2 to make the fish surface, (See Yme's topic) that's too much too. I don't want 120 mg/l, I want a stable 40 mg/l. I really ask myself if these levels like more than 100 mg/l are not damaging fish health. Not directly, but inderictly in relation to size and longeviness.

          Better watch plants, take CO2 slowly back until you get some problems, like BBA or stunting or if you start with BBA to begin with, gradually increasing until the side effects are ellaviated. This takes weeks of course, not a few days like using fish.

          I wish there was a reliable way too measure CO2 for the hobbyist, without investing in a $$$ CO2 meter. With light I can use my PAR meter and a somewhat useful graph can be made that most people can use, nutrients is easy too, I just add more than the tank needs.

          But CO2? I have good growth, and no algae except when I make mistakes myself. Still I'm in the dark. Do I have 30 ppm, 40 ppm or 80 ppm? I don't want 80. Or maybe it's just human nature to calculate everything and we have too learn too look at our plants.

          It's possible. Look at the picture of the Stellata.

          Beautiful plant which was over 9 inch wide. But look at the section in the middle. You can see that it's smaller than the lower and upper part of the plant.

          The period in which the plant grew smaller coincided with a period of higher water temperature. With higher water temperature CO2 demand rises. Apparently the plant got somewhat limited and grew smaller leaves for sometime. I didn't get algae in this period. When temperatures dropped, it grew back to it's original size.

          This tells me that I have a good CO2 level, but only for the water temperature I'm using. So I'm kind of at the lower limit. So using plants as a test works, but we have to be able to explain why things happen.
          That's not easy for a lot of people. Watching your plants carefully on a daily basis helps.
          Last edited by dutchy; 09-17-2010, 11:19 AM.
          regards,
          dutchy.

          My 2011, 2012 and 2013 AGA aquascaping contest entries:
          http://www.barrreport.com/album.php?u=21013

          Comment


          • #6
            Originally posted by scottward View Post
            Longevity of CO2 supply?

            Tom, those thanks that don't supplement CO2 (i.e. via CO2 cylinder, regulator etc), still need a CO2 source from somewhere don't they...and this CO2 source, in these cases, is coming from a specially composed substrate that slowly breaks down producing enough stable CO2 to support growth?

            Needless to say, these tanks that don't supplement CO2, would have to be very low light - with higher lighting levels this kind of result would be impossible without CO2 supplementation, correct?

            These non-supplemented tanks that look great are going to be fairly short lived aren't they? Eventually, whatever is supplying the carbon source (CO2 from substrate?), is going to run out.

            This excludes using, Excel etc, of course.
            Do not fish produce some CO2 and waste ,that is being broken down and used by plants along with possibly added ferts?

            Comment


            • #7
              I guess what I am trying to say is that fish produce some CO2, and waste from foods offered being broken down continuously ,would also contribute to CO2 levels in non CO2 injected set ups.
              So long as plant and fish load remained relatively stable I cannot see CO2 being depleted albeit present at low level.
              I will happily await thoughts on this as low tech,low light, low CO2 is currently what I am training my efforts on.

              Comment


              • #8
                You are correct. From what I have learned plants like a constant level of CO2. So as long as your parameters stay the relatively same in the tank, bioload, light, amount you feed, etc you should be able to maintain a natural setup for awhile. If you follow the setup that Tom lays out, you can use leonardite or peat to provide a slow release breakdown of carbon that your plants can utilize. As the fish produce waste this will help enhance the substrate and also aid in further decomposition which will produce some CO2.

                I have a tank that has been running for 3 years setup exactly like the walstad suggests in her book. Its a 6 gallon with 10 espei rasboras and some amano shrimp. After about a year plants started to stunt, but they came back much better when I started using small amounts of dry ferts. I'm not sure what the life is for these tanks, but presumably it should be a long time if balance is achieved. Getting to that point takes a good plan and to be willing adjust at signs of trouble before things get bad. For instance, I would change my water all the time, because I was paranoid, within days I would have a new algae outbreak. When I stopped doing this the algae was greatly reduced. You should do fine in your setup. If I had it to do over again. I probably would have setup my first tank as a low light no CO2 tank, rather then dive right into the CO2. I incorrectly assumed you needed CO2 and super bright lights to grow plants. Now I know better.

                Plus you eliminate the wonder that we all experience like laid out in this thread. How much CO2 am I really adding? What is the long term effect on fish related to elevated CO2 levels? Am I dissolving CO2 efficiently and effectively, although you do miss out on all the practical plumbing experience.
                Last edited by fjf888; 09-17-2010, 05:20 PM.
                Fred

                Comment


                • #9
                  somehow i posted a message 2x
                  Last edited by fjf888; 09-17-2010, 05:13 PM. Reason: please delete, double posted
                  Fred

                  Comment


                  • #10
                    Thanks Fred,

                    I think it shall be some time before I feel comfortable with the Gas, But I am reading,learning,and observing.
                    Dry fertz came today!

                    Comment


                    • #11
                      Tom can you tell us what the temperature was in both periods?

                      Comment


                      • #12
                        Well, I'm not Tom, but I suppose you mean me... I take that as a compliment

                        Normal temperature is 27 Celsius (81F) and elevated temperature was 32 Celsius (90F)

                        regards,
                        dutchy
                        regards,
                        dutchy.

                        My 2011, 2012 and 2013 AGA aquascaping contest entries:
                        http://www.barrreport.com/album.php?u=21013

                        Comment


                        • #13
                          You can sure do that :-)

                          Is 27 celsius your normal temp?
                          Mine is between 25,5 and 26.
                          So I am guess that I am fine with my 40 mg/l CO2.

                          Comment


                          • #14
                            Yes, 27C is my normal temperature because I keep discusfish.

                            Concluding just based on numbers you should be ok with 40 mg/l of CO2. You could use some more flow, up to 10x the tank volume. If you put your Eheim in manual mode and then push the + key a few times it will give you more flow. The only disadvantage is that the optional electronic gadgets don't work anymore. The factory setting of these filters is just 700 lph. But in manual mode, you can get 1100 lph. That's a lot more.

                            regards,
                            dutchy
                            regards,
                            dutchy.

                            My 2011, 2012 and 2013 AGA aquascaping contest entries:
                            http://www.barrreport.com/album.php?u=21013

                            Comment


                            • #15
                              Are you sure?
                              That is a big diffrence.

                              Not that I have any problems with it right now.
                              I can see leaves move every where, at least where the can move. The Pogostemon Helferi is not very flexible :-)

                              A other thing is cleaning the tubes. That makes a big difference.

                              Every thing is doing fine. We only need to rearrange the plants a bit to get a better looking scape.
                              That is where we are working on right now.
                              Last edited by dbazuin; 09-18-2010, 06:13 PM.

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