Air pumps below water level?

Discussion in 'General Discussions' started by Broder, Jun 16, 2016.

  1. Broder

    Broder

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    Most of the air pump manufacturers warn about positioning air pumps below the water level of the tank. Has anyone ever had a problem of water syphoning back if not mounted this way?
     
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  3. pHish_man

    pHish_man Discus

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    Yip, during load shedding last year lost 11 adult discus this way. Was a very traumatic lesson to learn.

    if you do put an air pump below water level PLEASE install a non return valve.
     
  4. OP
    Broder

    Broder

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    Very sorry that you learnt this in such a kak way Andrew. Thanks for sharing the lesson!
     
  5. f-fish

    f-fish #unspecified

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    Yeah ... - truth be told, CO2 is also best above the water level of a tank, non-return valves actually create a bit of back pressure CO2 is OK with overcoming this but for an air pump it really is best to keep them above the water lines. Take care when you are running a multi-valve air line or dual port pump, it only takes one tank to be lower to cause issues.

    Also do not forget a drip loop in the pipe - could help to keep water of your eskom plug.

    Later Ferdie
     
  6. Jwh

    Jwh

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    Yes, I don't think I've lost fish as a result, but the water does destroy the pump, ime the inline non-return valves that are available (I think I have tried every brand available) are pretty much useless in preventing this. I would go as far as to say, if you can't have your airpump above water level don't use one, rather use a wave maker if you need surface agitation.
     
  7. OP
    Broder

    Broder

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    Thanks for the warnings guys. I wonder how a syphon effect is created without a vacuum in the pipe? Is it just when the airline is very close to the water-level? Would it help to maybe create a loop 10 or 20cm above the waterlevel?
     
  8. howard

    howard

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    I think if you have a loop above the water line, it should stop the return. I would rather pay R17.00 and put a non return valve in for safety.
     
  9. OP
    Broder

    Broder

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    And you haven't had issues with the non return valves @howard?
     
    Last edited by a moderator: Oct 2, 2016
  10. howard

    howard

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    No I have been saved a couple of times by them. That's why I am happy to pay for one.
     
  11. pHish_man

    pHish_man Discus

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    @Broder

    The non return valves I use work just fine. The only time I had a problem with them is when I used them on my old bs hatchery where they would get clogged after a while with muck and salt and then not shut off properly. In that case I would toss them and pop new ones on.
     
    Last edited by a moderator: Oct 2, 2016
  12. DoubleDutch

    DoubleDutch Corydorasfan(atic)

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    Think the issue can be due to two causes/forces working together. When the pump in one way or the other stops pumping the air already in the line (under water) will "push back" and the waterpressure can "push" it over the edge. Second force working with it is adhesion (airline are quite thin/small) This two forces working together can make the syphoning start (third/fourth force : gravity / vacuum).
    A loop will help, but a valve is a better idea I'd say.
     
    Last edited: Jun 18, 2016

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