White film on coralline

Discussion in 'Water Chemistry' started by R34dawn, Jul 29, 2008.

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  1. ssgheislerswife

    ssgheislerswife Ritteri Anemone

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    Way too many pain meds bud, WAY too many!
     
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  3. PharmrJohn

    PharmrJohn The Dude

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    Ahhhh, but it is not in solution when it is part of a larger structure. If it is given the chance to re-enter the chemistry of the SW, then numbers are going to be changed. If it is ground down enough, it will dissociate (sp?)
     
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  4. ReefSparky

    ReefSparky Super Moderator Staff Member

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    No! You're missing the point. :)

    The larger structure of which you speak (the coralline algae) is made of a certain compound. Let's say it's calcium carbonate. If the calcium carbonate could become dissolved into solution in its present state it would simply melt off the rock and do so. If you were to grind it down to the finest powder possible, it still wouldn't go into solution without a chemical catalyst (a decrease in pH) to get the ball rolling.

    You postulate "If it is ground down enough, it will dissociate (sp?)" Not so!

    If that were true, there would be no need for such a device as a calcium reactors to change the bioavailability of the calcium carbonate found in a lump of coral skeleton. If it were that easy we'd simply grind down some aragonite and dose that into our tanks.

    The chemistry involved dictates a chemical change (burning the paper to ash) rather than a physical one (scraping the coralline to a fine powder).

    I hope that clarifies things a bit. :-/


    Perhaps someone with more chemistry under their belt or the ability to impart this could help me out. ;D
     
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  5. wareagle35031

    wareagle35031 Bubble Tip Anemone

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    im gonna guess number 2, but its a guess
     
  6. wildreef

    wildreef Stylophora

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    Well ya want a "WILDREEF" reply to it guys ? lol
     
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  7. Reeron

    Reeron Blue Ringed Angel

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    Reefspark nailed it. Unless you get the pH below 7 (as in a Calcium reactor), you will not get the white flakes to go back into solution. Hence, nothing will change, except you will have alot of white flakes floating around your tank.
     
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  9. wildreef

    wildreef Stylophora

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    Well I "if" said coralline was "scrubbed" with a stiff brush and this coralline had basicly fell into salution ( in the water colum ).
    I would definitly say that the MAG and CAL would raise , fairly significantly, now on the other hand DKH might move a bit bit up , but i think it would remain roughly the same.

    Funny though it's a good question, as to what would happen but ive never tried a test like that.
    But that's my "best ansewer"
     
    Last edited: Aug 1, 2008
  10. PharmrJohn

    PharmrJohn The Dude

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    Ooooooo, I like this discussion!!!! No, I do understand the point. I know what you are thinking and I can see where you are going with it. But Calcium Carbonate is an ionic compound. It is not a simple ionic compound like NaCl, but a complex ionic compound form that exists a lattice structure. So it does not necessary need a powerful catalyst to break it apart and dissociate it. More than Na+Cl- certainly. You only need water to dissociate that ionic bond. If the bond was covalent (electron sharing), then you would need something a little more harsh to catalyze the reaction (say heat and sulfuric acid together for a few compounds I used to work with in organic lab). In this case, I believe that the presence of water, heat and flow in the tank is enough to break the relatively weak ionic bond to separate it into it's cation (Ca++) and anion (CO3)2 components, given that the surface area is increased to a point where dissolution is possible (at a rate that is at least observable). The Mg++ from the lattice would also enter solution. An ionic bond is magnetic in nature. It does not take much.

    Looking back on it, and I will have to read up on it, I would hypothesize that the function of the Mg in the CaCO3 is to strengthen the lattice against breakdown. If it were pure CaCO3, the coralline would be in trouble. I am going to try to find a 3-D representation of the lattice. That would be interesting.

    Take a look at Tums. It is CaCO3. Good old Calcium Carbonate, used by those with stomach upset and women who need to suppliment their estrogen therapy to prevent, or slow, osteoporosis. One tums in a glass of water would be in solution the next day I'll bet ya!!! Especially if the water is at 80 degrees with flow added.

    Now, I don't know ANYTHING about Ca++ reactors. Totally clueless. I need to learn about those as I understand they are a plus in running a reef tank. So I cannot comment on that.

    Now, it has been 20 to 25 years since my chemistry courses, and I have forgotton quite a bit, admittedly, but this one I am pretty sure on. Thank God that is over. If I never see another chemistry book again I will be happy.

    Peace.......John.
     
  11. Reeron

    Reeron Blue Ringed Angel

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    Well, that Tums example assumes there is no Calcium Carbonate in the water already. Add enough Tums to saturate the solution, then try adding another Tums and see what happens. I would think nothing happens.
     
  12. Phayes

    Phayes Aiptasia Anemone

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    All i can say is MMYMEAHH (nerdiest sounding scientific exclamatory statement)... that was alot of chemistry.

    But im'a have to agree. You do need an acidic solution to break the matter back to its basic elements/compounds. Either that, or a high amount of heat may do the trick as well (and i'm talking hot). And thus, the answer to your question is "Nothing will happen except you make a mess of your tank- Congrats"

    Maybe, but that glass of water most likely isn't starting with a Ca of 450 or so, and a pH of 8.2.... That glass of water your talking about most likely has a pH of around 7...making it much more acidic to the calcium carbonate, thus converting it to simple salt and water (just like what happens when you take a tums when you experience gastroesophogeal reflux).