Why is it hard to keep Mag levels 'high'?

[dragoneggs]

Thanks Boomer... yes I plan to make a two Mag supplement with Epsom Salt and Magnesium Chloride, just purchased from BRS. My hope is I can raise the levels a couple hundred ppm to at least above 1300 and then just boost the waterchange volume with this supplement every month or so.

 

[mojoreef]

Dragin raising your Mag can be a bear, I have been their before and it took gallons to get it back to where it needed to be. One thing to remember when you are using any kind of mag suppliment is that you are not only adding mag but chloride and/or sulfate also. So try as best as you can to do it in stages.

Boom I am going by memory here (and that always gets me into trouble with chemistry) but doesnt dosing alk and or trying to keep a slightly high level run against the mag dosing?? as in pairs up if added at the same time or close??


Mojo

 

[Boomer]

No, it does not Mojo. You will get more ion paring of Mg++ but it just becomes part of the buffer. Most of the buffer in seawater is really ion pairs of Mg++, as MgCO3^o MgHCO3^o, where ^o equals x layers of water molecules or hydrated salts off Mg++. It will tie up more Mg++ for animals that use Mg++ but that is not really an issue as there is usually more than enough Mg++. Ion pairs as Ca++ may be more of an issue for corals with higher Alk with low Ca++. I think you are think'in it will tie up more CO3-- or HCO3 -, which it will but it still acts as a buffer in ion paring.

 

[mojoreef]

Yea thats what I figured but I was thinking but I was trying to relate it to when a person has low mg levels and is trying to raise them while dosing alk and maintaining a higher level of it?


Mojo

 

[Boomer]

I have never heard of that as an issue. It is more on the order of having high Mg++ and trying to raise it to a higher level with high Alk. It is not much different than Ca++. Now if you dump in a ample amount of Mg++, when you have high Alk, the issue here is the local high Mg++ and Alk, which gives a precip of Magnesium Hydroxide. When you dump in a buffer and see that white cloud that is almost always Mg(OH)2. 99 % of the time it is the guy in the mirror dumping in to much at once. Lastly, fresh carbonate sand or media loves to pull out both Mg++ and Ca++ out of solution, of which we call Hi-Magnesium Calcite surface growths on the carbonate grains. Even if this is done slowly, there is an issue, as fresh grains have a high affinity for Mg++, until an equilibrium is reached or the grains get coated with organics, which is usually the case.