Effects of low mag

[ndz98]

What are the effects of low magnesium levels in a reef aquarium? I can't remember but I thought I remember reading awhile ago that it can affect the way the corals take in calcium and alkalinity, correct? So if that is true, would having a low magnesium level stunt the growth of corals?

 

[Randy Holmes-Farley]

If magnesium is low, it can allow accelerated precipitation of calcium carbonate on pumps and such, but 1200 ppm is not likely low enough to have any noticeable impact on that. It needs to be especially low to be noticeable.

It is possible, although not really proven, that certain organisms such as coralline algae that are on the upper end of magnesium incorporation may sometimes grow faster at higher magnesium.

These have more:

Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-07/rhf/index.php

Aquarium Chemistry: Magnesium In Reef Aquaria ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/issues/oct2003/chem.htm

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-06/rhf/index.php