Calcium Usage

[Bergy]

I don't want you to feel like I am on a rampage against you or anything, Bill. I just have strong views about calcium and the need to dose it in heavily stocked stony tanks.

Oh, i agree with you and anyone else about the imortance of CALCIUM... no argument there.

And I have ZERO problem with your passion about this or most anything else i can imagine



I absolutely agree with you and anyone else about the importance about CALCIUM

I don't want you to feel like I am on a rampage against you or anything, Bill. I just have strong views about calcium and the need to dose it in heavily stocked stony tanks.

The tank/critters dont need magnesium.. Magnesium has nothing to do with coral growth or critters... DIRECTLY

...

If you were to do a CALC test and find out that it is off, when your ALK is on, then MAG is off...

Every single cell in your tank, be it bacteria, fungus, amoeba, invert, mammalian - you get the point - utilizes magnesium. All DNA and RNA replication, i.e. growth, is dependent upon it. Every single molecule of ATP (use for energy reactions in photosynthesis and digestion) incorporates magnesium, as does chlorophyll. In addition, it is incorporated into sponges, soft corals, and echinoderms as the mineral Calcite. Coralline algae deposits magnesium in its skeleton in proportion to its concentration in the water. It does get depleted, and surprisingly fast. It is one of the main reasons to do water changes...much moreso than calcium.

Im sure that we all need every element/chemical... Pretty much just like we need SODIUM... well, we dont really need the sodium as much as we need the NaCl.. and Just like we need Iodine.... also

But, I am sure that whatever the corals/critters needs is WAY BELOW the needs/thresholds of the significance of MAGnesium plays inthe  as you put it, '...THE HOLDING OF ALMOST HALF of the CARBONATE CONCENTRATION...'

Actually, the Magnesium doesnt HOLD anything... and i am not trying to say i can explain the process correctly, or even understanbly, but, as i have stated before,  MAGnesium plays a role with the how CALCIUM and ALK are processed through the water...

Without the correct relationship/ratio of MAGnesium, then there will be a problem in the ability of the saltwater to 'hold'/process CALCium/ALKalinity

Calcium being off with the Alkalinity on doesn't allow you to infer anything about the magnesium levels, and even suggests that they are correct since magnesium is responsible for holding almost half the carbonate concentration in NSW. It also mineralizes calcium carbonate, which crystalizes with a snowball effect, depleting both calcium and alkalinity. by adhering to the outer surface and preventing further precipitation and allows us to keep up with high levels we strive for.

this paragraph is kinda goin both ways...

you kinda say that if there is a difference between CALC and ALK then that is what MAGNESIUM is doing, but then you kinda say IT, (MAGnesium), '...also mineralizes calcium carbonate, which crystalizes with a snowball effect...'

So, does this mean, if you have MAGnesium it will create the 'snow storm'???

I could have sworn that the precipitation of the calcium was due to a the imbalance of CALCium to ALKALINITY ratio???


I am having issues with accessing reefkeeping mag and the chemistry articles... but as soon as i do, i will be glad to post what i can... as chemistry has never been my strong suit as it requires a lot of memorization... but the concepts are basic and logical... which to me will  better,  (hopefully) my points...

[Bergy]

ok, finally got my internet to cooperate.

here is the link to reefkeeping magazine article from Randy Holmes-Farely


http://reefkeeping.com/issues/2002-04/rhf/feature/index.php


I will read it now as i fall asleep, finally, hopefully... and then highlight what will be relevent to our discussion

[Bergy]

great article... i forget how good these articles are... pretty easy to read, and kinda easy to understand, at any level...

this means that although there is a lot to learn, no matter what level you are, you can get SOMETHING, maybe not everythng, but something significant from the article.. And if you re read the article you will get more


but for now.. I will post a few comments i read

Precipitation can begin when one of two things occurs:

1. Calcium carbonate seed crystals are added to the water. In reef tanks, the addition of fresh calcium carbonate sand will often suffice. This addition will initiate the precipitation of calcium carbonate (likely containing some magnesium and strontium as well).   
2. The supersaturation is pushed to unusually high levels. This can be caused by a rise in pH, a rise in temperature (as on a heater; Figure 1), or more obviously, by a rise in either calcium or carbonate.

This is kinda of importnat...Basically what this is saying is... We reefers usually want and create very high levels of calcium, and are basically on teh edge of precipitating, (snow storms).  And when we do that, it only takes a small event to cause the scale to be tipped...

To create a wider gap, or safety zone to prevent this precipitation....  yup, you guessed it... MAGNESIUM...

Still, even when precipitation begins, it is often stopped almost immediately by a combination of several things:

1. The most important thing happening in normal seawater to inhibit calcium carbonate precipitation is the binding of magnesium to the growing crystal surface. In a sense, it poisons the surface for further precipitation of calcium carbonate, forming a mixed carbonate of calcium and magnesium (the effects of magnesium are discussed in this linked article).
2. Magnesium also forms ion pairs with carbonate ions and thereby reduces their free concentration, making precipitation less likely.
3.  Phosphate adsorbs onto the growing crystal surface, inhibiting it just as magnesium does. In a reef tank this may become more important than in the ocean as phosphate is often elevated in reef tanks. This link provides some data on the binding of phosphate to aragonite surfaces.   
4. Organic molecules can also adsorb onto the growing crystal surface and inhibit further precipitation of calcium carbonate. Again, the process may be much more important in reef tanks where organic levels are typically higher than in the ocean (here's a link to a discussion and some data/calculations).

here is a paragraph that supports my suggestions to test ALKALINITY as an indicator, rather then CALCIUM

One of the interesting features of seawater is that there is a lot more calcium than there is alkalinity. By this I mean that if all of the calcium in seawater (410 ppm; 10.25 meq/L) were to be precipitated as calcium carbonate, it would use up a total alkalinity of 20.5 meq/L. In a less drastic scenario, let's say that calcium carbonate is formed from tank water starting with an alkalinity of 3 meq/L and that it is allowed to drop to 2 meq/L. How much has the calcium declined? It is surprising for many people to learn that the calcium would only drop by 20 ppm. Consequently, many aquarists observe that their calcium levels are relatively stable, but alkalinity can vary substantially. This is exactly what one would expect based on the fact that the tank already has an abundance of calcium.

there are several otehr related articles, (whichi appreciate as this keeps the article length down/shorter)

"A Simplified Guide to the relationship between pH, Calcium and MAgnesium"
http://reefkeeping.com/issues/2006-06/rhf/index.php

I will pick up that article tomorrow sometime, but for now, it is off to bed, again

[RandyFolds]

Im sure that we all need every element/chemical... Pretty much just like we need SODIUM... well, we dont really need the sodium as much as we need the NaCl.. and Just like we need Iodine.... also

But, I am sure that whatever the corals/critters needs is WAY BELOW the needs/thresholds of the significance of MAGnesium plays inthe  as you put it, '...THE HOLDING OF ALMOST HALF of the CARBONATE CONCENTRATION...'

Actually, the Magnesium doesnt HOLD anything... and i am not trying to say i can explain the process correctly, or even understanbly, but, as i have stated before,  MAGnesium plays a role with the how CALCIUM and ALK are processed through the water...

Without the correct relationship/ratio of MAGnesium, then there will be a problem in the ability of the saltwater to 'hold'/process CALCium/ALKalinity


this paragraph is kinda goin both ways...

you kinda say that if there is a difference between CALC and ALK then that is what MAGNESIUM is doing, but then you kinda say IT, (MAGnesium), '...also mineralizes calcium carbonate, which crystalizes with a snowball effect...'

So, does this mean, if you have MAGnesium it will create the 'snow storm'???

I could have sworn that the precipitation of the calcium was due to a the imbalance of CALCium to ALKALINITY ratio???

MAg doesn't create the snowstorm, it stops it. You quote the same thing from your article, but they say it "poisons" the process. The fact that we are trying to dissolve too many ions into solution is what causes the precipitation to begin with.

It does in fact "Hold" carbonate ions. It is kind of hard to go into without dragging a bunch of P-Chem with me.

The buffer system in seawater consists of CO2, H2CO3, HCO3-, and CO3--. For those ions (negatively charged) to stay in solution, there must be an cationic counterpart, Na+, Mg++, Ca+, B+, in equal concentration. At a pH equal to the pKa of a buffer component half the species are present as the acid-conjugate, and half are present at the base-conjugate. Salt and Magnesium actually drive the pKa downward towards a pH closer to natural seawater, and hence making seawater a better buffer between pH 8.0-8.5.

The ion pairing with magnesium actually increases the amount of "free", or bioavailable carbonate ions by "holding" them in ionic solution. Otherwise they would instantly crash out of the solution as insoluble compounds. It definitely holds them.

The precipitation of calcium is always happening, and is not caused by the imbalance, per se,  but is exacerbated by it. You say, "To create a wider gap, or safety zone to prevent this precipitation....  yup, you guessed it... MAGNESIUM...," but rather than magnesium, it is BUFFER, of which mag is a contributor.

The paragraph you posted about calcium levels vs. alkalinity isn't saying anything other than "most aquarists are too stupid to realize that 20ppm of calcium is only 1 Meq of alkalinity, and your calcium levels aren't stable at all, you are just comforted by a bigger number."

Again, you can't really infer anything about magnesium or calcium from an alkalinity test.

[Bergy]

i guessw we will disagree..

i alk is way low, and calc is good or way high, then i can derive that either the alk is off and i just need toadd buffer, or if i add buffer and it is still off, then i can derive that magnesium is probably off


and to test magnesium...

same would be true for calcium


typically, calcium and alk test, are consistant... and typically they are dosed together, erego TWO PART dosing solutions

Now, it would be really difficutlt to dose TWO PART solution when calc is good and alk is off...



you can cite all teh chemistry, but most of th etime you and i really saiyng the same thing, other then the ability to figure out if MAG is off by way of loking at indrect evidence


I did not say that magnesium is the cause of snow storms, but rather the extreme low ALK test result, or low ability to hold the ions, capacity of hardness

ultimately maybe it is teh experience of repeating tests and seeing rends in test results that lets me predict / feel what the tank peramters are att???




btw: i figured out the TEXT JUMPING THING when typing replys that are bigger/longer then the text box... you can actually drag the text box and make it biiger... there is a little spot in the middle line/bottom of the reply box... and you can drag it down or up...

way cool


btw:  im at gregs house and using ihis new biethdy toyu/laptop. and this monitor is huge

[cruzincaril]

if it makes you guys feel any better, im completely lost in this chemical discussion

[Bergy]

im partially lost so, no worries, but i still suggest you read that article from reefkeeping magazine on reef chemistry..

it is only 1-2 pages long and doesnt have any math or hard chemistry issues...

having read that will allow you to start putting some of the words you see here into some context...

if it makes you guys feel any better, im completely lost in this chemical discussion

[psykokid]

Alrighty then..

Todays Alk and Cal measurements are as follows:

Ca = 420 mg/L and Alk = 11 dKh

I haven't added any buffer or any sort of supplement to the top off water.

[psykokid]

survey says:

Ca = 400 mg/L and alk = 11 dKh

[Bergy]

have you tried any of the aquarium programs...  cant recall the names, but will look them up and send them to you.. I paid for one of them and used it for a bit... they keep track of your tank stuff and also ives ou reminders

Keeps track of coral age and growth.


i will look them up and let you know in a bit

[psykokid]

todays results:

Ca = 400 mg/l alk = 10 dKh

[Bergy]

and the calcium stayed level from yesterday???

Im not sure i would go less  then this...

and oh, btw, cant go to tom's on wedn, as that is my proceedure for my neck...

[psykokid]

Yup, same level as the other day.  I'm going to let things go and test tonite. After that i'll bring things back up. I'm going to average things and figure out how much supplement to add per day be it just the seachem, tech-cb, or kalkwasser

[Bergy]

I would still do a 'regular sized' water change and then test again after a few hours, to see how much calcium is brought back in...

then average...

but currently it looks like about 15-20 per day for calcium

[psykokid]

So things have held steady again at 400 mg/L for CA and 11 dKh for Alk. Not sure why the Ca and Alk usage has leveled off. Just for giggles i checked Mg and it was at 1400 so its right where it should be. I'm going to keep tracking for the rest of the week and see how things go. I have to wait till this weekend to do a water change because I'm out of salt and dont get paid till Friday. Tested nitrates the other day and they have started to creep back up from 25 to closer to 50 so its definitely time to do the water change.