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CO2 Dispersion & Circulation - Should this work?

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  • CO2 Dispersion & Circulation - Should this work?

    Obviously this is THE board for discussing this topic. Given all the folks who work very hard to insure that their tanks have good CO2 dispersion, I'm hopeful that I can get some feedback on what I have today and what I think I am going to do.

    I have 58G tank, planted pretty heavily. It's been up and running for 4 years or so. Lighting is 2x39W HOT5 plus a 22W T5. Doing EI with 50% water changes every 14 days. Subtrate is Flourite. Water is hard, kH is high. Using pressuring CO2 w/ a pH meter to keep my CO2 levels stable and avoid repeating the nightmare end of tank dump I've experienced before. Only run CO2 during the day. I'm diffusing it by letting it get sucked into the input into my Eheim 2026 canister. It makes some noise as it chops, and only very small bubbles seem to come out of the spray bar, so it appears that much of the CO2 is dissolved before it enters the tank.

    My big compliant/problem is that many of the plants I try to grow die off. Even rotalias, ludwigias, and some other "easy" plants wither and die off. Some grow, but most do not. I suspect that there are three possible answers:

    1) Light isn't high enough. I'm not sure this is the problem. I know it's tough to use the WPG calculations with HOT5s and T5s. My gut is that this is plenty of light to grow the simple plants that I am having trouble with.

    2) EI has been too low. It is possible I've been dosing too low. so I've recently upped some of those amounts. This is a pretty easy one to experiment with since the biweekly water changes reset things if something is out of whack.

    3) CO2 Dispersion - Personally I'm wondering if this is the REAL problem that I'm facing. As mentioned above, I'm using the 2026 to chop, and then I use an Eheim spray bar. It's mounted front to back on the short side of the tank just under the water level, with the spray going right to left. The back section of the bar points straight across the surface with just a bit of ripple, the middle section down at a 45 degree angle, and the piece near the front pointing down the right tank wall.

    That is the only circulation I have right now, and I'm not convinced it's enough. I was considering thinking of putting a Rio or Mini Jet on the back rear and blowing across the water, and then using that as a mister. But I really hate the vortex effect and don't want too much flow. Also, it appears the CO2 chopping is working pretty good as it, and it doesn't create a mist effect.

    So, here was my idea ------- I was considering sticking with the Eheim chopping method. and trying to up the flow with a Koralia 1. It sounds like they move water without the jet motion. I'm thinking that would help get the CO2 enriched H2o from the spray bar better circulated around the tank.

    As an alternative I was considering a small Rio and switching to the misting idea, and then I get both the mist and the additional circulation.

    I take it the MiniJet can't support the needlewheel mod, right? If so, how do you open it besides using a hammer???? I have one of those in my spare equipment box and could give that a try if it might work.

    IF anybody has any suggestions or ideas I would really love to hear them. I'm open to anything. It seems like I'm trying to do the right things, it's just the results aren't what I would expect.

    Thanks in advance for your advice!!!!

    Tom

  • #2
    Hi,

    I can see a few things that might give you issues.

    1. Light. Based on PAR measurements 2x 39 Watts T5 with reflectors are more than enough light to grow every plant you want, if your tank is not more than 18 inch deep. Less light means less CO2 demand so makes it easier to meet that demand. If you are using reflectors on the 39W's you can turn off the 22W.

    2. CO2. Although you have a pH controller, the number on the display will possibly not nearly tell you what your real pH value is. Water contains things like nitric acids with can influence the pH reading. The pH controller doesn't know the difference. I have seen variations up to 50%. That means that if you expect to have a CO2 level of 40 ppm, it could be 40, but also just 20 ppm. You should buy a good drop checker with a 4dkH solution and use that, or use the fish. As soon as they start to surface, you back off a little. Just take time to do that (days) and don't go shopping when you just adjusted the CO2.

    3. Flow. One Eheim 2026 is definately not enough. A good powerhead will give good results. But don't blow around the water too much. If all the plantleaves sway gently, you're ok.

    regards,
    dutchy
    regards,
    dutchy.

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

    Comment


    • #3
      Originally posted by tom855 View Post
      I take it the MiniJet can't support the needlewheel mod, right? If so, how do you open it besides using a hammer???? I have one of those in my spare equipment box and could give that a try if it might work.
      I ran mine through a mini jet for a while. There are two fingertip sized indents on each side where the intake is. Just push those two indents in, then pull on the piece where the intake in. Comes right off.

      http://www.fosterandsmithaquatics.co...5&pcatid=14665

      Check out the picture in this link, the inward circle towards the bottom of the pump is the indent.
      Last edited by csmith; 08-21-2010, 02:16 AM.

      Comment


      • #4
        If the Co2 mist is coming out from srpay bar, if the spray bar is long enough, maybe better to mount it across the tank at the back of the tank under the water surface around 1 inch. water flow if strong, can be limited by drilling more holes on the opposite of existing holes.

        the idea is to let water flow go through the surface, directly hit the front of the tank, then dive down to the front substrate (it helps a lot if HC is growing there), and then return to the back of the tank along with the substrate. So that makes a good circle of Co2. You can watch the tiny bubbles moving around the lower front of the tank if the route is set correctly.

        The issue is that if the growing plants reach the water surface, they will block this Co2 movement route, so timely trimming is a must just to keep the Co2 circle work.

        Comment


        • #5
          1. Light. Based on PAR measurements 2x 39 Watts T5 with reflectors are more than enough light to grow every plant you want, if your tank is not more than 18 inch deep. Less light means less CO2 demand so makes it easier to meet that demand. If you are using reflectors on the 39W's you can turn off the 22W.

          Wow! I don't know if I'm happy to embarassed. I've had this tank running for 4+ years and have tried all kinds of different things. Personally I love the HOT5 fixture from Nova I'm using, but it never occurred to me that what I'm using would grow most anything. I've always assumed it would only grow the low light plants and some medium light plants since that's all I ever seem to have success with.......at least on a good day. The Nova fixture are supposed to have pretty good reflectors, so I would tend to believe it's a pretty good light source. Having an HOT5 fixture that puts out that much light and has no fan is a wonderful thing.

          I will happily turn off the extra 22W T5 and make the assumption that the 2x39W is just fine in term of light.

          2. CO2. Although you have a pH controller, the number on the display will possibly not nearly tell you what your real pH value is. Water contains things like nitric acids with can influence the pH reading. The pH controller doesn't know the difference. I have seen variations up to 50%. That means that if you expect to have a CO2 level of 40 ppm, it could be 40, but also just 20 ppm. You should buy a good drop checker with a 4dkH solution and use that, or use the fish. As soon as they start to surface, you back off a little. Just take time to do that (days) and don't go shopping when you just adjusted the CO2.

          I've never really trusted the thing, but it's more of a rough guess and safeguard. I really like the idea of not just counting on a consistent bubble flow to keep things running. By putting the CO2 on a timer and user the SMS122, I can pretty much assure nothing is going to go bonkers and do a pH crash because of too much CO2. I've actually been in the process of creating some 4.0 kH solution for a drop checker I have, and will implement that asap. And I know what you are talking about about the fish. I've seen how they act when things are on the edge. It's pretty distinct.......except for the catfish which of course hang out on the bottom. THEY really take a hurting when the CO2 gets borderline. Anyway, message received loud and clear. Get the drop checker up and running.


          3. Flow. One Eheim 2026 is definately not enough. A good powerhead will give good results. But don't blow around the water too much. If all the plantleaves sway gently, you're ok.

          Another WOW! I've always been under the assumption that it was more than enough. It can really get things blowing if I'm not careful with the flow direction. But I guess with 5x the tank size at full throttle, it's just not enough. I will definitely invest in another pump of some kind to get things stirred up. I should have figured out some time ago that something was wrong when I noticed a distinct temperature delta as my hand got closer to the substrate. I should have known that I wasn't getting the water mixed up enough. Again, message received. I need more flow.

          I ran mine through a mini jet for a while. There are two fingertip sized indents on each side where the intake is. Just push those two indents in, then pull on the piece where the intake in. Comes right off.

          Cool. I'll give that a try. The mister idea might be interesting. It will also give me a bit of a clue about what the flow in the tank is doing. Plus, I have one sitting around. I'll be happy to try it out. Thanks for the tip on getting the thing apart.......without the hammer.


          mi5haha, I'm not sure I can implement the circle thing you mentioned because of my current scape, but it does tell me very clearly that I need to get the water moving all throughout the tank, just not in certian areas. I will absolutely give it some thought.

          Thanks all for the suggestions. You've given me some hope that I really CAN grow something in this setup. LOL. I've thought about giving up more than once because of the issues I've had. .......and I was ready to blame it on hard water. I will absolutely plan to report back on how things go after I implement some of your ideas.

          THANKS!

          Tom
          Last edited by tom855; 08-22-2010, 04:01 AM.

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          • #6
            I thought I would post my tank specs for you to compare:

            ~60 Gallon (48x18x18)
            4x54 W T5HO for 7 hrs/day
            EI Autodosing
            Eheim 2028

            So far I have gone through ceramic disc, mazzei, co2 reactor and now needle wheel.

            I have my Co2 setup so that a 350GPH needle wheel style pump is being fed with CO2 on an Eshopps overflow down to a 5 gallon bucket. I use a drop checker and it says light green for the whole day since the co2 is running 24/7.

            Growth is good with minimal algae growth.

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            • #7
              Boink,

              Well, one thing is very clear. I need to stir things up in the tank a bit. You have wayyy more light in your tank that's two inches more shallow than mine, but with more than 2x the circulation. I have got to believe this is causing the brunt of the my issues. Obviously different light levels work ok for different folks, but the common thing I'm missing is the circulation. I need to take a good hard look at my scape layout so I can get the circulation in here I need, and then add a good pump or something to get stuff moving around.

              Thanks very much for the input!

              Tom

              Comment


              • #8
                Tom,

                I was using one of the minijets for a while with CO2. If you have small enough tubing there's no need to take it apart, just stuff it in between the grates or find a way to have the co2 bubble up past the intake and get sucked in. Either would work. FWIW I'm currently using a disk directly under a Koralia to get the CO2 in there but I know it's not even close to good enough yet.

                -
                S

                Originally posted by tom855 View Post
                Boink,

                Well, one thing is very clear. I need to stir things up in the tank a bit. You have wayyy more light in your tank that's two inches more shallow than mine, but with more than 2x the circulation. I have got to believe this is causing the brunt of the my issues. Obviously different light levels work ok for different folks, but the common thing I'm missing is the circulation. I need to take a good hard look at my scape layout so I can get the circulation in here I need, and then add a good pump or something to get stuff moving around.

                Thanks very much for the input!

                Tom

                Comment

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