A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH

[Randy Holmes-Farley]

A new article:

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH

has posted at:

http://reefkeeping.com/issues/2006-06/rhf/index.php

The contents:


Calcium
Alkalinity
Calcium Carbonate
Solubility of Simple Solids
Supersaturation of a Simple Solid
Solubility of Calcium Carbonate
Calcium Carbonate and pH
Calcium Carbonate and Alkalinity
Calcium Carbonate and Magnesium
Summary of Abiotic Calcium Carbonate Solubility Effects
Summary of Biological Deposition of Calcium Carbonate
Additional Reading
Conclusion

[Billybeau1]

Simplified :eek2:

Next we'll need "Salt Water Chemistry for Dummies" :lol:

J/K Nice piece :D

[Randy Holmes-Farley]

Thanks.

I decided against the title to "The idiots guide to..." :D

[Boomer]

How did you sneak this by me ? I like cartoons:D I have one of each, a chem and physics book, full of cartoons explaining things. You should do more like this :D I always get "thanks for the post/article Boomer but I do not understand a word Randy said in that article" :lol: That "Chemistry for Dummies" book also use cartoons

[Hobster]

Thanks again for another great article. I am a bit confused however about the the last paragraph in the introduction about ozone?

"Through pictures and measurements, it is hoped that aquarists can attain an understanding of ozone's likely benefits before spending the time and money necessary to try it for themselves. While the results will not translate directly to every reef aquarium, my husbandry practices are not unusual and these results seem to reflect those found by a wide range of aquarists who have used ozone similarly"

[Randy Holmes-Farley]

Must have carried over at the web site from last month. Thanks. I'll have it removed. :)

[Randy Holmes-Farley]

All fixed now. :)

[Hobster]

And I thought it was Boomers job to keep an eye on you. :lol:

[Randy Holmes-Farley]

Now that he's dragged himself out of that pit for the last time, maybe he can! :)

[Boomer]

It is hard keeping an eye on Randy he is avery tricky guy at times :D Sometimes he knows how to make my eyes hurt :lol:

[Bojan]

Very interesting article. I have one very basic question, because I am not chemist.

If I understand correctly your article, then ...

If we dissolve NaCl in the water and solution is not saturated, that means, that there will nor be NaCl molecules in the water, but only Na++ and Cl-- ions . Is this correct ?

[Bojan]

I do not understand this sentence in the article

Abiotic precipitation of calcium carbonate, like coral skeletal formation, can incorporate other ions, such as magnesium and strontium.

Why is coral skeletal formation Abiotic precipitation ?

[Randy Holmes-Farley]

If we dissolve NaCl in the water and solution is not saturated, that means, that there will nor be NaCl molecules in the water, but only Na++ and Cl-- ions . Is this correct ?

It is not always true, but it is essentially true for sodium chloride. There may be some ion pairing of Na+ and Cl-, but not really any true "NaCl" molecules. Ion pairing is a very temporary association of ions in solution, so that they move together for a tiny fraction of a second before moving independently again.


Abiotic precipitation of calcium carbonate, like coral skeletal formation, can incorporate other ions, such as magnesium and strontium.

Why is coral skeletal formation Abiotic precipitation ?

Read it like this:

Abiotic precipitation of calcium carbonate can incorporate other ions, such as magnesium and strontium. Coral skeletal formation can also incorporate other ions, such as magnesium and strontium.

I meant that they are alike in incorporating other ions, not that the two processes are the same.

[Bojan]

Thanks. Now I understand.

[Randy Holmes-Farley]

:thumbsup:

Happy reefing. :)

[Bojan]

Is there any research how is Mg in coral skeletons related to Mg concentration in the water. I know, that different coral have different My concentrations in the skeletons, but how is this related to the Mg concentration in the water ?

[Randy Holmes-Farley]

I certainly expect that it drops as magnesium drops, but I've not seen such data. :)