cal and alk

Discussion in 'Water Chemistry' started by Brian_G, Apr 24, 2010.

  1. Brian_G

    Brian_G overly obsessed

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    so i have been dripping kalk for about 2 months with no problems. I had been maintaining my alk at about 9 and my cal about 450. today i tested and my alk was 10 and my cal was 350. I have no idea. even my Ph is dropped from the normal 8.2 to 8.08. ( I have a pinpoint ph hooked to my kalk reactor). Im not sure whats up.

    A-is there something that will raise the ph without playing with the alk or cal?

    B-any idea what might have caused the spike in alk and loss in cal with kalk?
     
    Brian_G, Apr 24, 2010
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  2. Brian_G

    tankedchemist

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    Measure the amount of magnesium in your system. If that is low, you could see this kind of problem
     
    tankedchemist, Apr 24, 2010
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  3. Brian_G

    Brian_G overly obsessed

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    I test mag once a month and last week it was 1560. haha

    i know thats really high. i over-dosed randy holmes recipe about a month and a half ago and it was at 1700.
     
    Brian_G, Apr 24, 2010
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  4. Brian_G

    tankedchemist

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    yipes. That could be related to your current issues. Mag, Cal, and alkalinity are all important for maintaining each other.... if one param is way off, there's a chance that the others are affected.

    Let's look for other sources of problems before we assume that, though.
    Increased pH might be caused by better oxygenation of your water. It's spring time,so have you just opened up your windows in the house? That would result in more oxygen in the air around your tank, which might cause a raise in pH. Also, are you measuring pH at the same time relative to your light cycle? Have you added a bunch of macro algae? These might also increase your pH.

    Do you have a lot of salt creep? And, do you put it back into your water ever? If you do and you don't put it back, there's a good chance that calcium is precipitating out faster than alk, thus explaining the dip in Ca. Increase in alk could be related to kalwasser dosing...

    Just throwing ideas out.
     
    tankedchemist, Apr 24, 2010
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  5. Brian_G

    Brian_G overly obsessed

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    well I did just recently open my windows but I noticed no change in ph. I have a ph probe on my kalk reactor. whenever my ph drops below 8.2 it turns my kalk on to drip and when it hits 8.3 it kicks off.

    so it usually drips at night.
    I dont have a lot of salt creep, I try to keep it clean and definitely dont re-add it.

    what are the side effects of having your mad too high though? I have never heard of any.
     
    Brian_G, Apr 25, 2010
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  6. Brian_G

    tankedchemist

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    I honestly don't know. Hopefully cc will see this and have a better answer for you. I'll think on it and see if I can come to any conclusions.
     
    tankedchemist, Apr 25, 2010
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  7. Brian_G

    ccCapt Reef Hacker Moderator

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    Your pH is fine at 8.08. There is no need to worry about it or try to make any drastic changes.

    As far as mag at 1700 ppm, there is no problem with it going that high. Some people deliberately keep it that high to fight some types of nusiance algae. You can have issuse when mag is too low where there isn't enough to keep the calcium and carbonates bound together and they precipitate. When you hear people can't raise their calcium because of low mag, what is happening is they ARE raising the levels, but there isn't enough mag to hold it in solution and it precipitates. That precipitation drops the calcium and alk levels and your back to square 1 again.
     
    ccCapt, Apr 25, 2010
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  8. Brian_G

    tankedchemist

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    Interesting. So, cc, any idea what could explain his dip in Ca with an increase in alk? I think that's the bigger problem, not the change in pH...
     
    tankedchemist, Apr 25, 2010
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  9. Brian_G

    ccCapt Reef Hacker Moderator

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    Being he's dosing kalk, his ca could have been near saturation and the next dose caused some precipitation and the drop. Alk can't rise without something being dosed to raise it. I would say that rise was a testing margin of error. We're only talking going from 9 dKH to 10 dKH.
     
    ccCapt, Apr 25, 2010
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  10. Brian_G

    Brian_G overly obsessed

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    so today i dosed enough cal to raise it 50 ppm so that should have dropped the alk a little.
    I tested my mag with saliferts mag test kit and it is still at 1600 after a 20% water change this weekend
     
    Brian_G, Apr 26, 2010
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  11. Brian_G

    ccCapt Reef Hacker Moderator

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    Why do you think dosing calcium will drop alk? It won't, unless you dose so much that you end up with a precipitation snow storm in your tank.

    What brand salt are you using and did you test the fresh mix for mag before you did the water change? Dropping mag levels with water changes are all about math. If your tank is sitting at 1600 ppm mag and you do a 20% water change with water that has 1400 ppm mag, your end result will only be a drop of 40 ppm to 1560 ppm.
     
    ccCapt, Apr 26, 2010
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  12. Brian_G

    Brian_G overly obsessed

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    I was under the understanding tha dosing all drops the alk a little dozing all drops the cal a little.

    I use reef crystals. The last time I tested mag for the fresh mix it was 1250

    I don't mind my mag being that high as long as it doesn't hurt anything. I could keep it there. It costs me almost nothing to dose mag.
     
    Brian_G, Apr 26, 2010
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  13. Brian_G

    ccCapt Reef Hacker Moderator

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    As long as your tank has "normal" water parameters, dosing either alk, calcium or mag will raise each of their respective levels. I would call alkalinity in the 7-11 dKH range normal, calcium in the 380-500 level normal and mag in the 1100 to 1400 range normal. You have a pretty wide range and as long as you stay within those parameters, dosing a supplement will raise the levels of that supplement only.

    You can run into issues when you have low alk combined with high calcium, or high alk and low calcium. or high alk and calcium and low mag. When you pass the saturation point by dosing either alk or calcium, you will see a physical reaction where the calcium and carbonates precipitate in your water column...aka precipitation snow storm. This precipitation is where the drop in either or both alk and calcium can happen. To a lesser extent, you can also see precipitation happening on your heaters, pump impeller and even the sides of your tank or sump can get coated with a precipitate.
     
    ccCapt, Apr 26, 2010
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  14. Brian_G

    Brian_G overly obsessed

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    Back when I first started my tank that happend and I had no idea what happened. I had a hell of a time getting it back to normal
     
    Brian_G, Apr 26, 2010
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  15. Brian_G

    sen5241b

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    You have to figure that although you dosed the same amount for months and it was fine --eventually the chemistry of your tank will change and you will have to periodically adjust your kalk drip. The growth or coralline can really suck alk out of the water.
     
    sen5241b, Apr 26, 2010
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