what is the cause of pH swing at night?

Discussion in 'Water Parameters and Additives' started by brettb2020, 12 Jun 2010.

  1. brettb2020

    brettb2020

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    what is the cause of pH swing at night? something to do with the lighting, but i dont understand how. and how is it stopped? remember reading something long ago about timing the light in you sump to switch on when you DT lights have gone off.
     
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  3. scubaninja

    scubaninja

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    Its because while the lights are on the corals take in carbon dioxide and produce oxygen as a part of photosynthesis which raises pH and at night the corals take in oxygen and produce carbon dioxide lowering the pH. Hence guys running kalk mainly at night and running a reverse light cycle in the sump:thumbup:
     
  4. brettb2020

    brettb2020 Thread Starter

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    that makes sense:) shot bud!
     
  5. scubaninja

    scubaninja

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    no problem bud
     
  6. SchyffS

    SchyffS Reef Aquarist

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    Also, as per scubaninja that is the major factor. The minor factor is that due to poor water surface agitation there is poor exchange of O2 and CO2. Also at night there is an increase of CO2 in the home and poor ventilation causes only more CO2 to be absorbed through the water surface causing a further pH drop.
    Posted via Mobile Device
     
  7. deadmeat2016

    deadmeat2016 Wouter

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    When lights are on photosynthesis happens in which algaes and things, taking in CO2, combining it with H2O to produce glucose(C6H12O6).
    when lights go out, algaes and things respire by using the glucose made during photosynthesis, like we do in our muscles, they need oxygen for this and releases CO2 which lowers the PH
    In all they take in more CO2 than they give off(usually) but i hope this clears things up for you as to why Alternating cycles are used :thumbup:
     
  8. brettb2020

    brettb2020 Thread Starter

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    ya makes all sense now guys:) thanks!
     
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