The Whole Water Change Thing

Discussion in 'Water Chemistry' started by ReefSparky, May 22, 2008.

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  1. ReefSparky

    ReefSparky Super Moderator Staff Member

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    I'm confused by something regarding water changes.

    Let's say to change 25% of your 80 gal system, you mix 20 gals of water up and complete the task Monday night.

    You've decreased the level of everything in your water by 25%.

    Let's now say instead you change 5 gallons each night starting Monday, and don't finish the task until Thursday.

    Is there a simple mathematical way to express the difference between changing 25% of your water both by a "one shot" representation, and again by a 5% per night over 4 nights method?

    In my mind, by doing it over 4 sessions, you're changing newly changed water Tuesday, Wed's and Thursday; and would hence be less ideal--but I could be wrong.

    Could anyone help me out here? :confused::confused:
     
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  3. aquaboy

    aquaboy Panda Puffer

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    no, as the nitrates etc would diffuse to be equal throughout water. Denser concentrations always move towards less dense, so your only taking out 5% of the pollutants that
    A.Built up during the day
    B. Those left from previous water change.
     
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  4. ReefSparky

    ReefSparky Super Moderator Staff Member

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    OK. So are you saying the net difference b/w the two scenarios is the second is more efficient because it removes the undesirables produced Tuesday, Wed's, and Thursday?

    If so, this would translate into the assumption that changing 5 gallons a week is better than changing 20 gallons once a month.
     
  5. aquaboy

    aquaboy Panda Puffer

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    Thats what i would think. The benefits
    A. Less stress because of change in params is lesser but more frequent
    B Would maintain lower levels. (Would have nitrate going high and then dropping after large water change but decreasing a bit each day, keeping it low)
    C.And would be much easier to do
     
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  6. GuitarMan89

    GuitarMan89 Giant Squid

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    I agree with this. changing fewer gallons more frequently will keep the overall level of undesirable compounds lower than one large change a month. Just before that one large change, pollutants will build up to a high at that time, then drastically changed, but will build up so that there will be a longer period of time when the pollutants are higher than when you do a smaller, weekly water change. This would result theoretically in a steady, slightly higher overall level of pollutants, but that level will not be nearly as high as a once a month change. Sorry if this is confusing of convoluted.
     
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  7. ReefSparky

    ReefSparky Super Moderator Staff Member

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    Not at all. Your response is concise and well thought. As is Aquaboy's. Thanks to the both of you.
     
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  9. aquaboy

    aquaboy Panda Puffer

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    Your welcome!! thats what im here to do! Help that is!
     
  10. BluePhish

    BluePhish Teardrop Maxima Clam

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    also works with the all the good stuff in new salt,trace elements,ect.....instead of letting those come to a extreme low once a month then replenished, they are replenished little by little over the month.
     
  11. omard

    omard Gnarly Old Codfish

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  12. ReefSparky

    ReefSparky Super Moderator Staff Member

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    Thanks for the info, Omard!;D