Durso standpipes and air problems

Discussion in 'Anything DIY Related' started by knut-ove, 28 Jan 2010.

  1. knut-ove

    knut-ove

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    I have a problem with lots of air in my DT:( I Bought the system used and had to redo the plumbing. The than is cycling, but has a lot of air that I so fare haven`been able to fix.

    I can se that the air is coming from my two dorso pipes.
    Tank has a central overflow with two dorso`s I have regulated the air intake of the dorso so the water level in the overflow box is about 2-3 cm lower then the tank.

    I can tell by looking at the pipe coming out again in my sump that the air is coming in cycles of about 2sec.

    My dorso is 40mm, but narrows down to 32mm going throw the bottom of the tank, then back to 40mm for the end stretch.

    Can water in the pipe have cavitation because of the reduction to 32 and back up again??

    Hope you understand what I am trying to say ...
     
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  3. jacquesb

    jacquesb Retired Moderator

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    Hi Knut-Ove. Are you still getting a lot of air-bubbles/micro bubbles in your display tank?

    Where is the water level in your return chamber, where your return pump is located?

    Can you post a side-on picture of your sump for me perhaps?
     
  4. knut-ove

    knut-ove Thread Starter

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    I`l go down and take some pictures right away jacquesb
     
  5. jacquesb

    jacquesb Retired Moderator

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  6. knut-ove

    knut-ove Thread Starter

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    Here are some pics:

    Not the best quality, but it gives you a view of the plumbing.

    [​IMG]

    Close up shoot from where the dorso comes out.

    [​IMG]

    Water level in the overflow chamber:

    [​IMG]

    Second dorso:

    [​IMG]


    Not so easy to see the water level, but it`s about in top of pic.

    [​IMG]
     
  7. keyaam

    keyaam

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    Can you take a full pic of the sump?
     
  8. jacquesb

    jacquesb Retired Moderator

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    Many thanks Knut-Ove. OK - so there are NO bubbles in your return section of your sump, where your return pump/s are located?

    Then - somewhere, your return pump MUST be sucking in air, in the piping going to the return pipe that ends inside your display tank....

    The fact that the durso standpipes are allowing air into your sump, is a "red herring" (meaning that you are staring into something that really does not matter).

    It is more the return chamber, return pump and return piping/plumbing that is where you should look for the issue.......

    How high is your return pipe outlet from the top of your water surface in your display tank? Is the return pipe outlet BELOW the water surface? If so - how far below? If not - it might be a case that the return pipe outlet creates a small vortex, which in turn is sucking air into the tank....
    - or: it might be a case where air is transported WITH the water that is coming from your sump (air being sucked into the piping somewhere), and this air is deposited into the display tank, together with the water coming from your sump
     
  9. knut-ove

    knut-ove Thread Starter

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    Here`s the pic:

    [​IMG]
     
  10. knut-ove

    knut-ove Thread Starter

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    Yes there is, lots of them :(...

    [​IMG]
    They are all bellow surface. The system is build up around a loop at the top, and small outlets around the top of the tank.

    [​IMG]


    Dos this give you any more to work with??
     
  11. keyaam

    keyaam

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    Try this

    1) Lower the level in your sump to the red line.
    2) As the tank is running you cant silicon baffles in place but try and get some perspex to create baffles (blue lines) which will break the bubbles
    3) try to get your overflow either behind the skimmer or in front with the elbow facing the left glass pane of your sump.

    Please let me know if it helps. try lowering the water level first then report back.

    [​IMG]
     
  12. jacquesb

    jacquesb Retired Moderator

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    Many thanks, Knut-Ove. Yes. It does help.

    Keyaam - I am just scared that lowering the water level, would cause the return pumps to suck even more air.

    I think that the amount of air-bubbles in the last chamber must be "removed" somehow.

    The baffles is one idea.

    Another possible idea, Knut-Ove - could possibly be to try and add some more live rock over your DSB, but stack the live rock on the right hand side of the DSB, that the live rock sits at the water surface (perhaps even let a small piece of live rock break through the water surface). This would interrupt the water flow at the surface, causing the amount of air-bubbles to be dissipated through the live rock stack. Try and ensure that the live rock is stacked all the way from the front to the back of the sump - creating a type of "wall effect"....

    If you cannot use live rock - perhaps anything else? Do you have access to plastic lighting diffuser, a.k.a egg-crate? Perhaps use some egg-crate..... Or something similar.
     
  13. knut-ove

    knut-ove Thread Starter

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    I`l do down and shift the LR around in the sump like you suggested.
    Just to see if I understand you correctly. You mean to stack them and make a wall just before the water comes to the return chamber??
     
  14. jacquesb

    jacquesb Retired Moderator

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    Yes, Knut-Ove. That is exactly what I mean. To interrupt the water before it goes into the return chamber (this is to break up the surface - that the bubbles/air that is travelling on the surface, to be "broken down")....

    This SHOULD decrease the amount of air-bubbles that you have in the water in your return chamber...
     
  15. keyaam

    keyaam

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    yes thats it
     
  16. knut-ove

    knut-ove Thread Starter

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    Great to have you on the team:thumbup:
    And I get a nice workout today running up and down the stairs :p
     
  17. keyaam

    keyaam

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    Any updates?
     
  18. knut-ove

    knut-ove Thread Starter

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    Yes, here is an update.

    Stacked the rocks like this:

    [​IMG]

    And here is a pic of the return camber:

    [​IMG]

    Still some air bobbles, but not nearly ass many. Looks like baffles might be the thing then??

    I am still a bit confused by the air coming down the overflow, but ......
    This tank is really giving me a ride for the money, but it`s still a nice way to learn.:whistling:......

    Guess I`l have to speed up my plan to build a new sump.
     
  19. jacquesb

    jacquesb Retired Moderator

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    Perhaps you can just try and get something like "egg-crate" (lighting diffuser) in the meanwhile?
     
  20. keyaam

    keyaam

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    Can you move the overflow a bit more to the left side?
     
  21. knut-ove

    knut-ove Thread Starter

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    I turned the outlet to the left side like you suggested.
    [​IMG]
     
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