I'm confused.... big surprise....dosing question

[AquaDiva]

I've been reading Randy's comprehensive articles. (part I, II III), and got to the one on supplementing magnesium...

http://reefkeeping.com/issues/2006-07/rhf/index.php

Now down towards the end of this article, he gives a receipe for dosing magnesium, but makes a note that it is not to be used for dosing with the two-part alk and CA...

So.... is this a new receipe, or is this to be used as just a stand alone mag supplement and you should be using the other receipe if you are dosing his Ca and ALK receipes....

he wrote...

3. Using both Epsom salts and MAG flake, dissolve 7¼ cups MAG flake and ¾ cup Epsom salts in one gallon of water, and use that to supplement magnesium in amounts determined using this linked online calculator, with the entry "Randy's Recipes 1 and 2 Versions A and B," and ignore for this purpose what those designations mean. This recipe is preferred, but its advantage over recipe #2 is minimal in most cases. .........

..........Note also that this recipe (#3) is different from that given in my DIY two-part recipe, because in that case more magnesium sulfate is necessary to offset the rise in chloride that is provided by both the calcium chloride and the magnesium chloride.

HELP please....

[bertoni]

That's a bit complicated a question. Are you using the DIY 2-part? If so, the third part can be dosed to help with Mg problems. Otherwise, I'd go with the recipe you quoted.

If you're using the DIY 2-part and you've dosed all the third part that's appropriate, and Mg is still low, then I'd suggest using the recipe you quoted to fix that problem.

[AquaDiva]

Glad to hear it is complicated, I feel a bit better about missing this....

To answer your question, yes, I am currently dosing Randy's two-part, but I am tapering off as the calcium reactor comes online.

I use the Mag supplement of the two part to also boost the amount of magnesium in my IO when I do water changes. I also add a bit of the CA part to up the CA in the IO. If I am understanding you correctly, if I am using the two-part, I dose the Mag supplement according to the original recipe as published in his two-part article. If I am just boosting my mag, then the recipe using on 3/4 cup of Epsom salts is a better alternative.

Did I get that correct??

[bertoni]

Yes, the Mg supplements from the DIY 2-part article should be used only when dosing the 2-part, and only to the extent outlined in that article. For boosting IO and when using a calcium reactor, the recipe 3 you quoted is correct.

[AquaDiva]

OK, last question.... I promise...

Would it be a bad thing to use the third recipe with the two-part, so you don't have to mix up two batches??

[bertoni]

The Mg recipe for the two-part would be preferable if you're not doing many water changes. If the water change rate is high enough, the general Mg supplement recipe that you posted is preferable. In the end, with most water change schedules, I think either would be okay.