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  • struggling to find CO2 balance and water change clues?

    Hello everyone,

    I've been having a heck of a time finding the lighting and CO2 balance in my newest setup. I don't have much of algae problems to speak of, but growth is far from optimal in some plants, primarily those who are poor CO2 competitors, ie rotala macandra green, HC, pogostemon stellatus.

    Today I changed the water towards the end of the day and noticed that my ATI light was at 18% power (on its way to OFF) when I finished and I still saw a great deal of pearling...pearling I do not see when the lights are up to their scheduled power of 40%. I know plants pearl very well after a water change, but could this be a clue as to how low I can set my lighting and still get good growth, or is this just a "happy" response from the plants only due to a water change.

    I figured I would reduce the lighting further and will be able to back off the Co2, it has been stressing fish. Could I back off to say the 20% level I saw the pearling at after the water change provided I found a good CO2 level? The trimmed stems of the hygrophila pinnatifida were pearling very well at the 18%, the HC like I have not seen except with water changes.

    Please share your thoughts on this. Thanks!
    Last edited by ShadowMac; 03-25-2012, 05:24 PM.

  • #2
    Generally Safe for Inverts & Filters; Do Not Exceed 2-ppm

    Hi Shawn,

    Technically all pearling means is there is photosynthesis and O2 saturation.


    A couple of possibilities come to mind, beyond the obvious that the water change is introducing a good amount of oxygen.
    1. The plants with current CO2 could use more light.
      1. Conversely, you could reduce CO2.
    2. Well into the photoperiod, 3 or 4-days after a water change add 1-ml of 3% Hydrogen peroxide per 5-gallon of water (do not do this if you are medicating the tank).
      1. If the plants begin to pearl, try it again 4-hours later (or the next day) with half the amount (0.5-ml/5-gal).
        1. If they pearl, 4-hours later (or the next day), try half as much again (0.25-ml/5-gal).
        2. If they do not pearl, 4-hours later (or the next day), add half again as much (0.75-ml/5-gal).
        3. At this point, the arithmetic is fairly simple, of course it can be taken any number of steps further, but… there really is not much to be gained.
      2. If the plants do not pearl go to step 3.
    3. You have high dissolved organic material.
      1. Test for that with PP (do not do this if you are medicating the tank) (this might cure what ails you, as well).
        1. 0.03-grams of KMnO4 for each 5-gallon of water reapplying as necessary until the water remains at least a faint pink for four-hours. Adding aeration is a good idea during test/treatment.
        2. If it required more than 0.1-g PP/5-gal then DOC is a definite problem.

    My PP recipe:
    I like 1% solutions since each milliliter of solution is 0.01-grams (10-mg) KMnO4.
    • 10-grams KMnO4 into 990-mililiters of distilled water.
      • In real life, I mix 10-g into 900-ml and “top-off” to 1-L.
      • Weighing is the most accurate way to measure water, but close is good enough.
    • Diluting 1-ml of the 1% solution with 9-ml of distilled water yields a solution that each milliliter is 0.001-grams (1-mg) KMnO4.
    • If you do not trust my calculations, Tug found a wonderful site run by the “Koi and Water Garden Society of Central New York” that has a PP Calculator.
    • To keep the numbers even I used 1.6-ppm, though up to 2-ppm is good.
    • If you think you have a parasite problem 2.0-ppm is a good number for the tank.
    Biollante
    The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

    Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
    • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
    • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
    • When in doubt "don't."

    Comment


    • #3
      Thanks Bio.

      would the fact I saw photosynthesis occurring give a clue at the light level I need to get growth? I don't have a PAR meter and this ATI light packs quite a punch. Since I want to minimize CO2 stress, I need to minimize the light without going too low. I've tried ranges from 30%-60%, if I turn the light up I will get pearling, so I don't think the system is O2 stressed..all it takes is more light. But I don't want to overdo the lighting. Now i'm wondering if i've been undershooting it. Pearling is noticeable at 40-50% and of course increases with greater intensity.
      Last edited by ShadowMac; 03-25-2012, 05:33 PM.

      Comment


      • #4
        Quantitative vs. Qualitative

        Hi Shawn,

        Yes I believe what you saw indicates low light, if what you are looking for is optimum growth. There is nothing inherently wrong with plants growing without pearling. As this seems to be a concern of yours (and many others) I simply offer a way to “know.”


        You may well be correct, the system isn’t O2 stressed. In this case, O2 stress isn’t really the issue, though on the flip-side it could be a symptom. Given the other things, you have mentioned there is a lot to be said for knowing.


        The above method is simply the quantitative analogy to the qualitative method you are employing, without spending a ton of money on various electronic devices.

        The above method may also add to your confidence in your quantitative analysis.


        Biollante
        The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

        Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
        • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
        • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
        • When in doubt "don't."

        Comment


        • #5
          I've done several WC's at night (8-9pm) in recent weeks Biollante and noticed the plants pearling away like mad as if the lights were on. I could only guess as to what that all means, so I won't...

          Comment


          • #6
            Just In Case This Was A Serious Reply, I Will Answer It As Such

            Hi,

            No need to guess,
            :gw it means by use of large water changes you are maintaining highly oxygenated water and removing wastes from the system and there is enough light for photosynthesis to take place. I have many aquariums and containers that are ambient lighting only that pearl on big water changes. Some pearl anyway.
            • If they are “pearling” in low/no-light then
            • it is not “pearling” in the sense we misuse the word,
            • it is simply un-dissolved air (bubbles) trapped vigorous by mixing.

            Large water changes are an effective method of dealing with water quality. Not unlike the way rivers and spring fed lakes operate.


            Biollante
            Last edited by Biollante; 03-25-2012, 10:53 PM. Reason: by 2nd air not oxygen
            The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

            Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
            • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
            • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
            • When in doubt "don't."

            Comment


            • #7
              trying to find the happy place

              those tests seem worthwhile and will provide me with more information to make a an informed approach to getting the best growth. The HC hasn't been carpeting well and some issues are noticed from time to time, but nothing I can really put a finger on. I have decreased surface agitation as it was considerable in previous weeks and reduced CO2 this weekend to compensate for less surface agitation. Today I'm observing improved fish behavior and better signs of growth, ie pearling. Come on Bio, it is pretty when it pearls

              Since I have decreased surface agitation I will be aerating at night to enhance gas exchange.

              I would like to know for sure, so I will complete those suggested tests to see what happens.

              Comment


              • #8
                I made sure it was not trapped air...I witnessed the gas leaving the cut ends of a stem of hygrophila pinnatifida as well as damaged portions of HC. It was without a doubt "pearling"

                Comment


                • #9
                  Too each their own.

                  Hi,

                  I do not know if Squidly’s comment was serious or a sad attempt at a “gotcha.”
                  • A couple of years ago I offended a bunch of people over “pearling.”
                  For most, it really doesn’t matter that we understand how things work, just that they do. I push buttons on my phone and I talk to whoever is on the other end…


                  Pearling isn’t that big of a deal to me, I guess a little light pearling is nice.

                  In some cases, the pearling makes it look “sweaty.”

                  I also am aware that folks photographing their tank often like to do that the day after a large water change.

                  I am also aware some cheat, amazing what a shot of Hydrogen peroxide or a dose of Sodium percarbonate can accomplish.



                  Biollante
                  The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

                  Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
                  • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
                  • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
                  • When in doubt "don't."

                  Comment


                  • #10
                    Poor Mr. Beedle...beatle..

                    i didn't consider that squidly's response may have been sarcasm...

                    oh well...

                    I guess my conundrum has been what light level is enough to get growth and are there clues I can go by without buying a PAR meter, which essentially is what you have provided above in your first post. Today the tank looked good, but one day doesn't translate to much. A week or two will tell the truth of it.

                    Thanks for your help as always, Biollante.

                    Cheat with photos!? :O never! who would do that?!

                    I often forget that most of the photos we see are poor representations of what is to be reasonably expected. For the most part, i compare growth in my tanks to each other especially when they contain the same plants. For example, the HC in my 12 gallon is doing superbly while the HC in the 48 is doing poorly. S. repens in 7.5 gallon and 12 gallon doing great...48, poorly. So something is going on with the 48 that isn't with the others. Flow is ample, i have a large filter and an MP10...that leaves CO2 and light. I had hoped that the water change pearling was evidence I could reduce lighting substantially and focus primarily on CO2 for a similar result. However, no matter how much I try without a water change that kind of metabolic activity doesn't occur in my plants until the light gets around 40% power.
                    Last edited by ShadowMac; 03-26-2012, 01:38 AM.

                    Comment


                    • #11
                      Eyes, Fingers, Nose, Brain

                      Hi Shawn,

                      We also have to consider the possibility that the plants, the system are simply telling you what they need.


                      So much of the balance, I think Tom Barr said this well in Robert H’s podcast this past week, is the balance in how well various plants compete for CO2 and light.

                      Really, this is what we are doing as we inject CO2, choosing the levels and how much light in relation to the plants we pick.


                      While the internet is a wonderful resource, I think the level of deception, often passed on by well-meaning folk, sometimes self-serving, sometimes just nasty is incredible. At least the expense and accountability of magazines and books tended to ameliorate the content.

                      For all the test equipment I have gotten, I really do not think test equipment or test kits are particularly important. I think what you are doing, gaining experience and coming to understand your plants, critters and systems, subjectively that is qualitatively, is for more important to your success.

                      I think it is far better to spend your money, not to mention time and effort on the plants critters and quality equipment rather than PAR meters and sophisticated equipment.

                      A PAR meter is nice but US$200,buys a lot of plants.

                      Most of what you need or want to know quantitatively can be learned by use of a few basic chemicals and household items that are cheap and readily available, or can be arithmetically found.
                      • Most of us can measure pH with our fingers accurately enough for most of our purposes.
                      • A piece of soap can tell you about the makeup of your water.

                      Biollante
                      The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

                      Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
                      • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
                      • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
                      • When in doubt "don't."

                      Comment


                      • #12
                        I wasn't trying to be sarcastic, I was merely mentioning the observation I had and thought perhaps pearling has something to do with the difference in surrounding gas and the energy stored in the plants. But then, that's why I grew algae until recently. Sorry for any confusion!

                        Comment


                        • #13
                          No worries squidly! Luckily my problems haven't grown algae, just poor growth in some species.

                          Bio, I've definitely improved a lot in my abilities as a an aquarium keeper. Balancing fish and plant species has made it a longer process than if just focusing on one of the two. What you said is spot on, the CO2 hogs in my tank are the ones doing the best. I need to get things to work for the ones who do not compete as well. I'm getting closer and closer.

                          Comment


                          • #14
                            If this helps, I struggled to find the proper Co2 level for my 100g tank for several years. I'd been given the advice from someone much wiser than me, to drop the Ph level 1 pt. down from the base starting Ph, and go down from there until the fish got queasy. Although I found the desired level with relative ease after a few attempts with knowledge, I could never maintain that Ph level consistently until I installed a Ph controller.

                            As the much wiser Biollante mentions, this is another piece of equipment, and the plants are much more interesting to look at. In my experience however, had I made the controller purchase first I would have saved me a zillion bucks by now as I killed a lot of plants! (well the algae did...). Now, no matter how many plants I add, or how much the surface is exchanging Co2/o2, the controller compensates automagically. Works great, as long as your probe is accurate...

                            Comment


                            • #15
                              Originally posted by Biollante View Post
                              Hi Shawn,

                              We also have to consider the possibility that the plants, the system are simply telling you what they need.


                              So much of the balance, I think Tom Barr said this well in Robert H’s podcast this past week, is the balance in how well various plants compete for CO2 and light.

                              Really, this is what we are doing as we inject CO2, choosing the levels and how much light in relation to the plants we pick.


                              While the internet is a wonderful resource, I think the level of deception, often passed on by well-meaning folk, sometimes self-serving, sometimes just nasty is incredible. At least the expense and accountability of magazines and books tended to ameliorate the content.

                              For all the test equipment I have gotten, I really do not think test equipment or test kits are particularly important. I think what you are doing, gaining experience and coming to understand your plants, critters and systems, subjectively that is qualitatively, is for more important to your success.

                              I think it is far better to spend your money, not to mention time and effort on the plants critters and quality equipment rather than PAR meters and sophisticated equipment.

                              A PAR meter is nice but US$200,buys a lot of plants.

                              Most of what you need or want to know quantitatively can be learned by use of a few basic chemicals and household items that are cheap and readily available, or can be arithmetically found.
                              • Most of us can measure pH with our fingers accurately enough for most of our purposes.
                              • A piece of soap can tell you about the makeup of your water.

                              Biollante
                              Well put.

                              Thanks
                              www.BarrReport.com

                              Comment

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