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Dosing General Hardness

Discussion in 'Advanced Strategies and Fertilization' started by Gill Man, Feb 23, 2005.

  1. Gill Man

    Gill Man Prolific Poster

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    I have a question regarding GH and dosing Mg and Ca. Is anyone using either Seachem's or Kent's GH+? I checked Kent's website to see if they gave ratio of Ca to Mg. the MSDS link, http://www.kentmarine.com/msds/BOTANICA_GH.PDF shows < 20% for each component, which I take to mean that their solution is variable.

    I have both these chems available separately, but wanted to use up the rest of the 2L container. I go through about 100ml per week after w/c for my 90G for a GH of about 5 dKH.

    I know we're looking to sustain a 4:1 ratio, Ca to Mg, but I don't remember reading why. I know some people add MgSO4 to their CSM+B mix, doesn't this change the 4:1 ratio and do they then add back Calcium?

    I'm not worried about maintaining a steady dGH, knowing it can go up some without any problems, but I would like to get a handle on how to dose these two cations during the rest of the week. Also, if anyone has any "tricks" to dissolving calcium, please let us know! I have been thinking about gettting a stir plate, perhaps even with heat, to have it all mixing without having to attend to it. Thanks.

    If your responses could reference dGH instead of ppm that would be great.
     
  2. Ian H

    Ian H Guru Class Expert

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    Re: Dosing General Hardness

    My tapwater is quite soft and low in Gh. Although I can't answer your question with any authority I'll be lurking on this thread as I need to understand the importance of the chemicals that constitute permanent hardness and their effect on plant growth.

    Ian
     
  3. fosteder

    fosteder Guru Class Expert

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    Re: Dosing General Hardness

    About dissolving CA....CaCO3 is a pain in the rear to dissolve. I have heard that CaCl2 dissolves much easier. I will be able to tell you how easy in a few days, I have a shipment coming in from www.GregWatson.com
     
  4. chubasco

    chubasco Guru Class Expert

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    Re: Dosing General Hardness

    This GH+ also has carbonates/bicarbonates in it to boost your KH? Your above
    statement doesn't make sense unless it does. GH is sulfates and chlorides
    which you get from Epsom salt (MgSO4) and Calcium Chloride. Carbonate
    hardness (temporary hardness) is from carbonates/bicarbonates where most
    of us just use baking soda (sodium bicarbonate) to raise it's level to 5 dKH. I
    don't want to be pedantic on stuff you already know, but do you have the
    water report from your city or county? That'll be your baseline for what needs
    to be added. There's people that run their tanks with 10-12 dGH with great
    results, but you have to have at least 5 dKH to go with that. The 4:1 ratio
    of Ca to Mg is for good cell transport, both plants and fish. You have to keep
    track of what the tapwater has already (Ca&Mg) and treat your changewater
    with it, not the tank. I'm for fert the tank, but treat the changewater for
    whatever parameters, it needs, separately. That dispenses with any mistaken
    overlap. YMMV,

    Bill
     
  5. Gill Man

    Gill Man Prolific Poster

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    Re: Dosing General Hardness

    My bad (first time ever using this slang). I meant 5 dGH. According to the packaging and website, Kent's GH+ contains magnesium and calcium salts, which, I guess could be anything including CaCl2, CaCO3, MgSO4, etc. I was wondering if I need to add calcium back into the tank if I'm adding MgSO4 along with my CSM+B. Sounds like it, to get close to a 4:1 ratio.
     
  6. chubasco

    chubasco Guru Class Expert

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    Re: Dosing General Hardness

    I myself wouldn't add MgSO4 with the CSM+B to the tank. I'd do a test for
    GH then add Ca/Mg 4:1 to bring it up to at least 7 dGH. That way, the 2
    components are in proper ratio, tho I don't know if this is an absolute, maybe
    3:1 would be adequate, too. As I said before, I like to keep water treatment
    and water column fertilization separate, so I don't mistakenly double up on
    one or more components.

    Bill
     
  7. Laith

    Laith Lifetime Charter Member
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    Re: Dosing General Hardness

    My tap water is a bit ridiculous when it comes to GH. I have a GH of 14 out of the tap but the vast majority of it is Calcium... very little Magnesium.

    It took me a while to figure out that my plants needed more Magnesium even with a GH of 14 out of the tap.

    As to Calcium, CaCl2 dissolves readily in water.
     
  8. Tom Barr

    Tom Barr Founder
    Staff Member Administrator Social Group Admin

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    Re: Dosing General Hardness

    CaCl2 for Ca
    MgSO4 for S and Mg
    CacO3 for both Ca and KH
    Baking soda for KH

    SeaChem Equilibrium for Ca, Mg, K, Fe, Mn
    It's a good product for many things and very useful for non CO2 tanks when dosed once a week.

    Regards,
    'Tom Barr
     
  9. chubasco

    chubasco Guru Class Expert

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    Re: Dosing General Hardness

    I concur, after placing three 1/8" chips of Greg's Calcium CaCl2 in a
    half-filled beaker of water: with gentle swirling it completely dissolved in
     
  10. Ian H

    Ian H Guru Class Expert

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    Re: Dosing General Hardness

    OK all well and good, but how do I know if my tank is deficient in calcium and magnesium? And what is this 4 to 1 ratio about and how do I calculate and achieve that, if I need to.

    Ian
     
  11. chubasco

    chubasco Guru Class Expert

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    Re: Dosing General Hardness

    Ian, you will have to do a GH test on your water to find if you're deficient in
    Ca and Mg. That won't separate into whether it's Ca or Mg, so having the
    water report from your water company is helpful. If it shows that you have
    a predominant quantity of one or the other, you will have to factor accordingly
    :)

    Can you guys in Europe get these water reports? Or has the government decided you don't need to know the "accepted level" of arsenic, cyanide, and
    the like. When I was stationed in Fallon, Nevada, cyanide was 10% above its
    "accepted level." I drank bottled water judiciously, while there....

    Bill
     
  12. Gill Man

    Gill Man Prolific Poster

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    Re: Dosing General Hardness

    Since my first posting, I started using my new La Motte CaCO3 test. With this value and dGH and formulae, I can calculate Ca and Mg concentrations. After my 70% waterchange, I got a calculated value of 15.2 ppm Ca and 7.41 ppm Mg. I added enough CaCo3 to increase my Ca to about 30 ppm, so now I have 4:1 ratio of Ca:Mg. It also increased my GH by about 1 dGH and Kh to 2.25 dKH. Which is exactly what I was looking for in my dosing general hardness post.

    I understand my test kit only measures CaCO3 and not Ca but it gives me the approximation I was looking for without dosing Ca and Mg too blindly.
     
  13. chubasco

    chubasco Guru Class Expert

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    Re: Dosing General Hardness

    How much does a La Motte CaCO3 test, cost? Being able to separate the 2
    in measurements is a handy tool!

    Bill
     
  14. Gill Man

    Gill Man Prolific Poster

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    Re: Dosing General Hardness

    Ok, so I just did a KH test and it is the same as before I added the CaCO3, so I feel confident to say that adding CaCO3 does nothing to raise KH.
     
  15. Roman

    Roman Lifetime Charter Member
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    Re: Dosing General Hardness


    I don't know for the rest of the Europe, but here in Slovenia I can get water report, but there is no Ca or Mg in it :mad:
    You can check it here, it's in pdf format. I guess I'll need to ask them for Ca and Mg, but I somehow doubt about getting answer.

    There is like 14 mg/l SO4 and 6 mg/l Cl, but I don't know if this information is of any value.

    Roman
     
  16. Laith

    Laith Lifetime Charter Member
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    Re: Dosing General Hardness

    The carbonates in CaCO3 will raise your KH... eventually! It just takes that stuff forever to dissolve and impact KH and GH.

    Baking soda (sodium bicarbonate) dissolves immediately and has an instant impact on KH without affecting GH.
     
  17. Nillo

    Nillo Junior Poster

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    Re: Dosing General Hardness

    Doesn't baking soda impact pH? Would you need to make up the water well in advance?
     
  18. Laith

    Laith Lifetime Charter Member
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    Re: Dosing General Hardness

    Yes, forgot to mention that. Raising KH will raise your pH as well!
     
  19. Gill Man

    Gill Man Prolific Poster

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    Re: Dosing General Hardness

    It raised my GH after a few hours. Why wouldn't it be measurable in a hardness test immediately? I understand the KH part, how it will increase slowly over time as it dissociates.

    I did adjust the KH with sodium bicarbonate. I just stir 2 tsp. in glass of water then dump it in the tank (90G). pH goes up a littel as we would expect. Once the ph controller brings down the pH (about 5 minutes later) I add another aliquot and repeat until I get to my KH target level. I've been doing it this way for years. If it takes that long for CaCO3 to dissociate, then I'm not gonna worry about it. :D
     
  20. alexperez

    alexperez Prolific Poster

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    Re: Dosing General Hardness

    Gill Man,

    I quote "Since my first posting, I started using my new La Motte CaCO3 test. With this value and dGH and formulae, I can calculate Ca and Mg concentrations."

    Could you tell me how you did that?
    I have the La Motte Hardness(4824-DR-LT) and the La Motte Alkalinity (4491-DR) are these the same test kits you have?

    Thanks!
     
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