Magnesium Question

What role does Magnesium play in a reef tank?

Is the main concern that Magnesium will get too low or too high?

Can anyone recommend a good test kit? My LFS was asking over 40 for pretty much every Mg kit. They seem cheaper online but I want to make sure I don't get a crap one.

Thanks,
-AJ

 

As to the role, it plays a three way part with Ca and alkalinity. I believe it inhibits Ca from precipitating out of the solution, and allows proper proportions of Ca and alkalinity. I have a salifert test kit and really like it, easy to use, you get a good amount of tests out of it, and it's a very good quality kit.

 

I use the RedSea Mag kit, but I hear Salifert is ok too.

 

Mg test kits are usually up there in price compared to say a pH kit....

I like my Mg 1500-1800, which to many is very high(too high). Mg helps to balance out Ca and Alk, If one drops check the others and you'll see one has dropped. They work together. I never realized this and went for 5 years with a tank that was crazy fluctuating, then I learned about Mg. I raised it and my Ca and Alk started to stabilize.

 

Mg2+ takes the place of Ca2+ to make MgCO3 instead of CaCO3. The Ca2+ is thus freed for uptake by livestock, while the MgCO3 bond is still weak enough to allow CO3 2- to buffer the pH.

There are two measures of hardness--general and calcium. General measures hardness with respect to Ca, Mg, and a few other trace elements. Calcium hardness measures just Ca concentration.

Natural seawater has Mg levels of around 1300 mg/L.

 

I use an elos MAG test, I like it alot.

 

Salifert or Elos are good test kits
Enjoy: Chemistry and the Aquarium

 

Cool thanks for the info...

 

Great link Otty.