Magnesium...

[wsonner]

How important is magnesium supplementation when trying to increase Ca using Kalk or other Ca sources? What about Moly and Strontonium? I'm sure this must beget a "that depends" answer but I was hoping to get a good thread going on the topic because it seems confusing. Ok, I guess this is the real question....if you want to keep your calcium and Alk levels right for calcerous algaes and hard tube tube worms etc....what is the easiest way/best way to do it? Believe me...I've been reading everything there is to read for the better part of 13 years but the more I read, the more questions I have, know what I mean?

So, what's the formula for something to which I KNOW there really can't be a formula,ahahah.

 

[Greg Hiller]

>if you want to keep your calcium and Alk levels right for calcerous algaes and hard tube tube worms etc....what is the easiest way/best way to do it?<

That depends upon your useage rate of calcium and alkalinity, and the important of convenience vs. price, both short term and long term costs. Randy H-F covers this topic very well in the following article:

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm

>How important is magnesium supplementation when trying to increase Ca using Kalk or other Ca sources?<

That question is also addressed in detail in another of Randy's articles:

Magnesium in Reef Aquaria
http://www.advancedaquarist.com/issues/oct2003/chem.htm

The paragraph from that article that you are probably most interested in is posted below. Randy said it far more eloquently that I could:


Effect of Magnesium on the Calcium/Alkalinity Balance in Aquaria

How does magnesium impact the balance of calcium and alkalinity23 in reef aquaria? In order to answer that question, one has to have a basic understanding of the calcium and carbonate systems in seawater. These systems have been discussed in detail in a variety of previous articles, so I won't go into them here in great detail. In short, calcium carbonate (CaCO3) is supersaturated in seawater,24 meaning that given enough time calcium ions will interact with carbonate ions and precipitate as calcium carbonate. If you push the concentration of either too high, CaCO3 will start to precipitate. Magnesium interferes with this process, permitting both calcium and carbonate to be elevated above where they would be in the absence of magnesium.