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CaCl2- 2(H2O) in my stock solution?

Discussion in 'Aquatic Plant Fertilization' started by pat w, Oct 27, 2011.

  1. pat w

    pat w Member

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    I auto dose and mix up a stock solution for macros (KNO3, KH2PO4, and K2SO4) and trace (CSM+B, and pinch more B) about once a month. I also dose CaCl2.2(H2O) at each water change since I olny have 15ppm Ca at my tap. I've checked solubility and I should be ok including the CaCl2 in with the macros but I just wanted to run it by the brain trust to make sure I wasn't about to do anything grossly dumb.

    I also add MgSO4 at water change (Mg is 0.045ppm at the tap). Would that be a possible candidate for the trace solution?

    Pat
     
    #1 pat w, Oct 27, 2011
    Last edited by a moderator: Oct 27, 2011
  2. Biollante

    Biollante Lifetime Charter Member
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    If You Are Not Part Of The Solution You Must Be Precipitate

    Hi Pat,

    Happiness I think is going to be dosing the Calcium chloride separately a couple of times a week or even once in a larger dose at water change time.:)



    The biggest problem is the Calcium phosphate, Ca[SUB]3[/SUB](PO[SUB]4[/SUB])[SUB]2[/SUB] you will create, which is close to insoluble.:(



    The Epsom salt works well with the trace, CSM+B contains some.:)


    Biollante

     
  3. Aquadream

    Aquadream Guru Class Expert

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    I am confused!!! Where the Ca3(PO4)2 will come from?
     
  4. Philosophos

    Philosophos Lifetime Charter Member
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    CaCl2 is something I use, and it doesn't play nice with most other ferts in stock solutions. Calcium in general, is hard to keep bioavailable and suspended in the presence of other fertilizer salts. For me, it's one of two elements (the other being phosphorous) that prevents a cost-effective 1 bottle stock solution.
     
  5. Aquadream

    Aquadream Guru Class Expert

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    I use CaCl2 for a long time as part of GH booster solution. Never had any problem. Also plants do not use much Ca++. Fish can get it all from food.
    In stock solution CaCl2 is ok only with other Cl based salts.
     
  6. Philosophos

    Philosophos Lifetime Charter Member
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    As a GH booster, sure. It's the all-in-one that's a problem. It's an issue of getting calcium to sit well with phosphate, and being able to afford all the micronutrients bonded to Cl. After that, I have a passing wonder about residue drying out with a combination of tons of Cl, and nitrogen. NCl3 isn't the safest stuff in the world.
     
  7. pat w

    pat w Member

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    Thanks all for the info.

    MgSO4 now part of the traces. Still dosing CaCl2 at water change.

    Pat
     
  8. Biollante

    Biollante Lifetime Charter Member
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    reactants recombine to form two different compounds, each of the products having one


    Hi,

    You needn’t be confused, Calcium phosphate is one of the double replacement reactions that take place where aqueous reactant compounds swap their ions when one of the compounds is a Calcium compound and another contains phosphate (or phosphate is available).
    :)

    I am not sure how Dan gets NCl[SUB]3[/SUB] out of it since most folk work hard to hurt themselves with that stuff.
    :confused:

    Make up a solution of any of the Potassium compounds, make another solution with a Calcium compound and you will see some precipitate form, it may stay suspended for long periods, say if one of the compounds is Potassium nitrate.

    If one of those compounds happens to include phosphate or is a phosphate, than a heavier precipitate will form and sink quite quickly.

    Were you to pour of the liquid and let the precipitate dry you would have some clunky rock like stuff that is for most practical purposes not soluble in water, with a solubility product constant (Ksp) of 2.07 X 10[SUP]-33[/SUP], compared to the marginally soluble Calcium sulfate, Ksp of 4.93 X 10[SUP]-5[/SUP].

    Biollante
     
  9. nazrm

    nazrm Prolific Poster

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    If CaCl2 reacts with PO4, when to dose it? Can it be dosed at the same time as CSM+B and MGSO4?
     
  10. Philosophos

    Philosophos Lifetime Charter Member
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    nazrm, I do it as a third item to dose. Also, I never dose it; between my water supply and food, the quantities are sufficient.

    Bio, I'll leave you to wonder.
     
  11. Biollante

    Biollante Lifetime Charter Member
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    No Worrys


    Hi,



    In this thread, we were discussing stock solutions, relatively speaking very high concentrations compared to our aquariums.:gw


    Let us say we are “dry dosing” a hypothetical aquarium with a net 50-US gallons of water, about 189-liters.


    • We have decided to dose 1-gram of KH[SUB]2[/SUB]PO[SUB]4[/SUB] that will add about 3.7-ppm PO[SUB]4[/SUB][SUP]3-[/SUP] and 1.5-ppm of K[SUP]2+[/SUP].
    • We also add 10-grams of CaCl[SUB]2[/SUB] that adds about 19-ppm of Ca[SUP]2+[/SUP] to the water column.
    • If you mixed them thoroughly as you dosed the double replacement reaction would leave something like 2.3-grams of Ca[SUB]3[/SUB](PO[SUB]4[/SUB])[SUB]2[/SUB] as precipitate.

    We find that the solubility of Ca[SUB]3[/SUB](PO[SUB]4[/SUB])[SUB]2[/SUB] is 0.002-grams per 100 grams of H[SUB]2[/SUB]O at 20C,

    • which as luck would have it is the temperature of our hypothetical aquarium.
    • Oh the joy!:rolleyes:
    We remember that by definition liter of water weighs 1-kilogram, 1000-grams, therefore we reason each liter of water can dissolve 0.002-g X 10= 0.02g of Ca[SUB]3[/SUB](PO[SUB]4[/SUB])[SUB]2[/SUB]. :)
    Since we have 189-liters of water and 2.3-grams of Ca[SUB]3[/SUB](PO[SUB]4[/SUB])[SUB]2[/SUB]

    [SUP]2.3-g Ca3(PO4)2[/SUP]⁄[SUB]189-l[/SUB] = [SUP]0.012-g Ca3(PO4)2[/SUP]⁄[SUB]l[/SUB]


    We quickly realize that the force of the water is greater than the ionic forces holding the Calcium phosphate together so,
    for joy, both the Calcium and the phosphate along with the Potassium and chloride will remain or shortly be in solution.


    So as long as you are dry dosing, I wouldn’t worry about it.:cool:


    Biollante

     
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