Mike
I have read the "marbles in bucket analogy" and so has Randy and we both say it has holes in it
for example if your Ca is much higher than your alk, adding carbontes will not raise the alkalinity because the imbalance will casue situations where it is not incorperated into the water chemistry properly or precipitates out...
That is not so at all. Of course you can raise the Alk and without any precip. It is an issue of how high you raise the Alk to get precip. If your Ca++ is 450 and the Alk is 2.5 meq / l it is not an issue to raise it to 3 or 4 meq / l without precip. But if you brought it up to maybe 5, 6 or 7 meq / l , especially if the pH was high.....poof....CaCO3, snowstorm.
Lets call Ca++/Alk balance at 410 ppm Ca++, Alk 2.25 meq/ l, pretty much NSW in any seawater chem book with a pH of around 8.2. We call balance between Ca++ and Alk as for every 20 ppm Ca++ you need 1 meq / l. Meaning, if you are at 410 and what to rise the Ca++ to 430, you "should" raise the Alk from 2.25 to 3.25 to be in a Ca/Alk balance. What is often misunderstood and not explained is this balance, even though the answer is right there in front of you.
Lets pretend precip is taking place by coral, coralline, abiotic, etc. This is forming CaCO3. For every 20 ppm Ca++ that leaves solution to make CaCO3 you need 1 meq / l. Ok, think........seawater has 2.25 meq / l and needs 20 ppm Ca++/1 meq / l to make CaCO3, which yields 50 ppm CaCO3 as Aragonite or Calcite. So, 2.25 x 20 ppm = 45 ppm Ca++ and 410 -45 = 365 ppm Ca++. That means that if all the Alk left solution to read Zero Alk, to form CaCO3, there is still 365 ppm Ca++ in the water. Now where is the balance ? Balance here would mean if your run your reef tank at 365 ppm Ca++ the Alk should be zero to be balanced. Make any sense ? How does the bucket analogy fit in here ? But that is balance. Our balance scheme more or less is around NSW and we go from there, within reason. Most peopel do not have their Ca++/ Alk at balance. It does not have to be balanced, just within a traget zone.
...you won't get the balance back right?
IO salt usually is around 360 -380 Ca++ with an Alk of 4 meq/ l, so it is way out of balance
To be balanced IO should have an Alk of 1 meq / l. And what does everybody do to bring it in balance ? Raise the Ca++ with Calcium Chloride to say 420-450.
Check Randy's and Craig's article on this Ca++ and this Alk thing. You will see where they state if the Ca++ is to high and you want to bring it down and back into balance add buffer to increase the Alk to bring down the Ca++. I don't like this idea and Randy or Craig are not hot on it either.
But yes Mike I understand what you mean
Just don't be using the Marble bucket thing.
Balance for me is NOT just Ca++, Mg ++ and Alk but all those other ions that are out of balance, SO4, Na++, Cl- etc. How often have you seen someone post that their Alk is normal or their Ca++ is normal and they try to raise one and it goes right back to where it is. Pretend their Ca++ is 380 and the Alk is 2 meq/ l "Why can't I get my Alk up", Why can't I get my Ca++ up" are the ? With theses levels there should not be an issue of raising either but there is. This is a tank that is out of balance and only water changes will fix it. The tank has set is own new balance based on its chemistry, which is not the balance WE want. If you do regular water changes balanced or even having Ca++ and Alk out of balance is not an issue in raising either as long as you don't get carried away. Such is often not the case when there are no or few water changes. Some of this is brought about by the reefer himself by adding or changing sup's from x to y, sometimes because Bob said to do this, then Henry said to do this then Judy said to do this. As Randy said "Consequently, trying to correct one problem can cause another" and "these links can lead to serious problems if they are not fully understood."
I use to use a method that would tell me if the tank was leading to an imbalance visually. I would take a small amount of SeaChem Labs Marine Buffer and add it to warm water in a glass, let it dissolve and then dump it in the tank. An imbalance can be seen visually by what happens when it hits the tank water. A cloud will form and if that cloud is gone in a few seconds the tank is balanced. The longer it takes for the cloud to dissipate the more imbalanced the tank was. A bad tank may take 1 to 2 hrs to clear or white transluscent blobs would form and float around.
