Raising Magnesium

[melev]

Hi Randy,

I can't seem to raise the magnesium in my tank. Thought I'd give you my method, and hear your thoughts.

The system is 280g, with about 240 or more pounds of LR. The sump holds another 70g.

I'm using Magnesium Chloride, one of these pelletized salt melt products. Mixing two cups worth in a cup of RO/DI water, I add that to my system gradually over 10 minutes.

Typically, I only think of this about every two weeks. So today, I tested my water and the level was 1050ppm. I added 2 cups, waited an hour, and tested it again. 1050ppm!

So I added another 2 cups, waited impatiently about 15 minutes, and had 1050ppm. Argh.

I know the goal is 3x the calcium level in the tank, and my calcium is 520ppm. Alk is 14.7 dKH, an unintentional result of dosing excessive Kalkwasser. The CO2 has been turned off to my Calcium Reactor for the past week or more, and the regulator has yet to consume what little bit is left within it.

Salinity is 1.025 (refractometer)

So there you have it. What do you think? Just add another pound? :rolleyes:

[Randy Holmes-Farley]

You likely need more, yes, although I can't rule out a faulty kit as well. I'd target natural levels of 1280 ppm, not triple the calcium level.


This calculator shows how much should be required (in you case,more than 2 kg if I entered the values correctly):

http://home.comcast.net/~jdieck1/chem_calc3.html

[melev]

So, four pounds would be quite a bit. Thanks for that link. I'll keep adding more each day, to not dose it all at once.

[Randy Holmes-Farley]

Sounds like a good plan.

Good luck. :)

[melev]

Out of sheer laziness, what do you suggest I do to add it to the tank? Put it in my top off container? Set the cup on top of the tank with a hole in the side so it drips / trickles in?

If I'm pouring it in, I pour it in front of the Tunzes a shot at a time until it is all dispersed. Since it isn't as concentrated (or doesn't raise Mg as fast as I expected), am I worrying about nothing?

[Randy Holmes-Farley]

I'd dissolve it in fresh water, and pour in enough all at once to a high flow area away from organisms to raise magnesium by 100 ppm each day.

[melev]

Thanks. Yesterday, 4 cups were added with zero ppm. :lol: Why am I worried? :rolleyes:

[Randy Holmes-Farley]

Are you sure it was a magnesium supplement? :D

[melev]

Yes. It is called MAG Ice Melting Pellets (Magnesium Chloride). I guess I could just pour in the bag. ;)

[SaltyPugs]

I've been using the Seachem (Dry) Stuff...but it hasn't moved much...but I've been adding it to my top off water with Kalk and Strontium (also dry)...is this a bad idea?

[Randy Holmes-Farley]

Yes, that is a bad idea. :D Magnesium precipitates from limewater as magnesium hydroxide. The strontium is OK in limewater.

I discuss both of these in this article:

Magnesium and Strontium in Limewater
http://www.advancedaquarist.com/issues/dec2003/chem.htm

[SaltyPugs]

Thanks Randy...I was afraid of that.

What the best (cheapest) way to raise it? Maintaining seperately is fine...I'll just mix up a batch of the strontium/magnesium and add that to my tank twice a week (although it's easier to add to top off water :D ). But first I want to bump it up by 200 ppm in a 120g tank...what would you suggest.

[Joao Cotter]

From the commercially available products in the aquarium trade, I've used Tropic Marin's Bio-Magnesium and Kent Tech-M with great success to raise magnesium.

[Randy Holmes-Farley]

Most of the aquarium magnesium products are likely fine. I don't know which is cheapest among them.

If you can find magnesium chloride, then a mixture of it and Epsom salts is a much cheaper way to go. This article and thread have details:

A Homemade Magnesium Supplement
http://web.archive.org/web/20030624220704/http://www.animalnetwork.com/fish2/aqfm/1999/june/bio/default.asp

DIY Mg additive
http://archive.reefcentral.com/forums/showthread.php?s=&threadid=554952

[melev]

Hey Randy, here's one for the old "did you double-check...." list:

I just opened up my new Salifert Magnesium test kit, and immediately noticed it has the bigger blue spoon for the powder (reagent 2). In my last kit, I had the little white spoon (like the Nitrate kit). Today my Mg is 1380 ppm. As I was doing the test, I was already planning my next post: "How do I lower magnesium?!!!!!!" ;)

Salinity 1.025
Alk 13.6 (coming down again)

[Randy Holmes-Farley]

OK, we'll blame Habib, :D

FWIW, I'd just leave the 1380 ppm alone. :)

[melev]

Cool. I guess now it is time to tackle strontium for a while.

And maybe I should start a <b>new</b> thread :lol: about lower phosphates in your forum. I bet that is never asked. Mine are way up there, near 3.0 as of last night. Hey, maybe it is the wrong spoon again! hehehe

[Habib]

Marc, the spoon doesn't matter. ;)

You're welcome in the Salifert forum to talk about your Mg kit. :)

[melev]

I'll be there in a second.