Aeration, when is it sufficient
  • squarerootsquareroot February 2012
    Posts: 4
    Hi! greetings to all! This is my first post, I have been following posts since the old forum. I have only been lurking and learned alot. Now, I would like to ask from the kichis here regarding aeration....

    I am just curious regarding sufficient aeration. How would we know if it is enough or not without the koi/s dying?

    My pond is roughly 10 cu.m. and I have a Resun LP60 aerating the pond and also share line to my bio filter. I also have a small falls for additional aeration. I would like to ask, is there an engineered computation of proper aerating our koi pond?

    I found somewhere in the internet that the DO in a koi pond should be around 5-5.5mg/L. How do we compute that with the given: pond size and pump capacity?

    Thank you in advance.....
  • HDCuHDCu February 2012
    Posts: 1,117
    Only way to check dissolved oxygen is with a DO meter. 5-5.5mg/l is the minimum. The nearer to saturation the better. One easy way to check if you need more aeration is if you add more aeration do your kos appetite improve and/or become more lively. If they do then additional aeration is justifiable.
  • harryyewharryyew February 2012
    Posts: 396
    Bro squareroot

    Please see link below on how I have computed the aeration requirements.

    I have verified the DO calculations with actual DO readings using a calibrated DO meter. The calculation is representative.

  • ikankoikauikankoikau February 2012
    Posts: 1,053
    Bro squareroot,

    I believe that enough aeration would be "enough at the most lowest oxy level". The least oxy level in the pond in normal situation(not under treatment) is early in the morning around 3 to 6am. This is when the pond experience reverse photosistesis and algea or plant in/around the pond releasing CO2 rather than providing O2. If your kois are not swimming near the surface trying to catch it's breath, then the aeration is sufficient. This is just my way of "listening" to the kois.

    Obvious method is by using DO meter. Still it has a few consideration such as temperature, location of water spot and etc. So the reading can varies depending on spot location and time of the day. That's why I would prefer to "listen" and observe the kois.


  • %5BDeleted+User%5D[Deleted User] February 2012
    Posts: 0

    as captain said.."listen" to them.i was there and been kois have enough/sufficient o2 but when it comes to active,you can see how they eat and swimming around.before they were just "lazy".eat a few and play a while and inactive.when i add more aeration,you will see them become more active,eat more,play more.
  • squarerootsquareroot February 2012
    Posts: 4
    Wow, thanks for your posts bros.

    Bro Harry, I've read your thread, engineered indeed. It may not be as perfect but we can consider it as basis.

    With your permission, is it ok, to copy and paste the computations you made?

  • harryyewharryyew February 2012
    Posts: 396
    Goodday bro squareroot problem.

  • squarerootsquareroot March 2012
    Posts: 4
    Ok, thanks Harry.

    I will try to simplify the formula. For any questions how the formula arrived, you can refer to Bro Harry's thread. :P

    For Koi weight computation, you can try this site:

    A.) DO @ 30 deg C = 7mg/L
    B.) 1 Kg of Koi = 900 mg of O2/ hr.= 21,600mg/day or 0.0216 Kg/day
    C.) Food intake convert to ammonia @4%

    1. Air required for Koi:
    Give Total weight of Koi: NK

    O2 req'd = NK x 0.0216 Kg/day = ___________ Kg O2/day

    2. Air for ammonia nitrification:
    Give feed rate = ________ grams/day : FR

    Ammonia level = C x FR = ______ Kg/day ; AL

    O2 req'd = 3.55 x AL = ___________ Kg O2/day

    3. Air for DO:
    Give Pump size = ________ m3/day ; PS

    O2 req'd = 4 mg/L x PS x 0.001 x 24 = ___________ Kg O2/day

    TOTAL O2 REQUIRED: 1 + 2 + 3 = __________ Kg )2/day : TO2

    Air requirement: TO2/ 0.02016 = ___________ m3/day : AR

    Factor of Safety (FS) : 1.5

    ARS: AR x 1.5 ________ m3/day

    Convert to L/min:
    ARS (1/24)(1/60) = ________ L/min

    Please use at your own risk. Bro Harry said his computation is close to the DO meter reading. I myself has not confirmed the accuracy of this computation but we can start from here.

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