Will this reactor work

Discussion in 'Carbon Dioxide (CO2)' started by Always Broke, 11 Mar 2010.

  1. Always Broke

    Always Broke Member

    Messages:
    226
    Location:
    Penryn Cornwall
    Thinking on how to introduce the Co2 into my 760 ltr set up.
    As it has a sump filter system I was thinking of adding the Co2 there. I thought that I could perhaps make a chamber that would mix the Co2 better. There is a box in the last section of the sump from which the return pump sucks from. Co2 is introduced into this via a diffuser and rises up into the power head where it gets mixed and returned to the suction part of the box.
    Would this idea work.
    Or am I better going for a pair of Aquamedic 1000 reactors in parallel. I would use two so as to not restrict the flow from my pump. The hose tails in the reactors can be removed and larger ones fitted which would also help with flow . I could of course use two pumps but that means two spray bars in the tank.

    Co2Reactor.jpg

    Simon
     
  2. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Hi,
    I don't think it really matters all that much whether you inject into the sump or whether you use some external diffusers. The problem is whether or not the sump is sealed. an open sump, especially one that has lots of churning will out-gas the CO2 like a can of coke. If you seal the sump then it will do a much better system-wide job of retaining the CO2. If you minimize the splashing within the sump this will also help a lot.

    Cheers,
     
  3. Always Broke

    Always Broke Member

    Messages:
    226
    Location:
    Penryn Cornwall
    My sump will be fairly well sealed . There should be no surface disturbance apart from the water entering the sump and with a bit of thought that should be reduced to a minimum.

    Simon
     
  4. Steve Smith

    Steve Smith Member

    Messages:
    4,428
    Location:
    Leamington Spa, UK.
    Will their be enough oxygen for the bio media/bacteria if your sump is well sealed? Forgive my ignorance on that :)

    As for reactor, you seem very handy with DIY projects, so maybe building a DIY reactor would be the way forward? Ed Seeley has a write-up which could be customised to your needs by changing pipe sizes etc :) Check it out here:

    viewtopic.php?f=20&t=4626
     
  5. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    No worries, forgiven mate. :thumbup:

    Photosynthesis works like this:
    carbon dioxide + water + light energy --> carbohydrate + oxygen

    So healthy plants saturate the water with a higher oxygen content than what would be achievable with strictly an open sump and air/water interface. Sealing the sump helps retain the CO2 (so this maximizes CO2 availability to the plants) and simultaneously helps retains the higher dissolved O2 content which maximizes O2 availability to fish and bacteria. :clap:

    I was chewing on the two options for a while and I'm leaning towards the in-sump solution, only because it seem like the return pump will be a higher capacity than an external canister? If so this should give a better distribution, but I don't have a firm grip on the system-wide schematic so it's not clear to me whether the option is to use the same return line as an input to the external reactor or whether the external reactor would be driven by a separate pump.

    The other disadvantage of an external reactor is the pressure loss due to constriction at the reactor inlet. If the piping diameter is kept the same then this is less of an issue. Also you'd have to mount the reactor somewhere wouldn't you? So overall, might be better to do in-sump injection... :crazy:

    Cheers,
     
  6. Always Broke

    Always Broke Member

    Messages:
    226
    Location:
    Penryn Cornwall
    The reason I did not want to use in line external reactors was the flow restriction. I intend to use a high volume low pressure return pump. With this I hope to be able to circulate a lot of water with out it going at "3000" miles an hour
    This means building some sort of in sump reactor.
    In the drawing I am using a power head or similar type pump to help mix the Co2 with the water. This water is then presented in the chamber where the return pump gets its water from. I have been thinking it might be better to use a couple of smaller power heads and have two Co2 feeds to help mix things up even better. This is all things I can experiment with. The main thing is that I need to create an efficient reactor chamber within the sump.
    As you pointed out in the post above the Plants are providing the O2 for the bio stage just as in a canister filter set up.
    I will have a go at making something and see how we get on.
    First will be how well the power head mixes the Co2 with water. I can try this in a small test tank. I am thinking that there will be an optimum amount of gas a given size of pump will mix. Once I have found that I can work out how many I might need.
    I am also working on the water change system.

    Simon
     
  7. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Hi,
    I wouldn't get too wrapped around the axle with reactor design. A simple mounted ceramic disk diffuser (or group of diffusers) to get a CO2 mist is really all that's needed I reckon. By the time the CO2 finds it's way through the sump and back to the tank it should be fairly well mixed. All you really have to avoid is having big blobs of gas building up in the chamber (or causing pump cavitation). Remember, you've got to able to disassemble and clean these things occasionally, so the simpler the design the better.

    Cheers,
     
  8. JanOve

    JanOve Member

    Messages:
    25
    Location:
    Ålesund, Norway
    An alternate solution to making a reactor or using a diffuser is simply to feed Co2 into the inlet of the return-pump.
    Here`s a crappy picture of my sump, used a Aqua Medic tee to connect the Co2 hose. Works like a charm :D
    Gets a nice mist from the return-outlet.
    Return.jpg
     

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