[StirCrazy]

[quote="danny zubot"]

IMO you don't want to super load your tank with any one substance. Mg is a slowly depleting element in a reef, much more so than Ca and Alk etc. If you add too much Mg (which we know is needed to make Ca bio available) you run the risk of precipitating the access Mg with Ca+ in you system, and will cause your Ca levels to drop faster. This was noticed in my tank once as aragonite turning into rock. I don't believe it is harmful to your corals, but it is a waste. I would keep your Mg at the high end of normal, around 1350 ppm, at this level your corals can best optinimize Ca consumption at around 350 to 400 as stated above.

When my Mg levels are down I notice less Ca consumption when testing, which correlates to less coral growth. Hope this helps

couple things, Mg doesn't make Ca "bio available" if you read the articles Bev have been posting every chance she gets I believe there is one that explains how Mg works in great detail, if not ask and I will find it and post it. but for a short version Mg simply coats Ca to prevent other stuff from bonding to it and dropping it out of solution so with out the proper amount of Mg Ca will participate out of solution. I guess if you want to say that makes it Bio available in a round about way it could be but it is a very misleading statement.

Also normal Mg levels are 1300 to 1400 ppm so 1350 is dead middle. there have been some tests done on higher Mg levels and it becomes a mute point after the "normal" range and it will take a much higher level to cause harm as nothing will use Mg except for the Ca ions themselves, but having said this I don't want people just to dump indiscriminately to raise Mg, always measure and raise it no more than 200ppm / day or so.

Steve