Mg Help needed

[superfirefly]

I have never tested for Mg before but I have always had trouble getting Alk and Ca balanced so I thought it was time. I ran the test with a salifert test kit and it showed 1170. From what I understand I should be aiming for 1300. I purchased Seachem Reef advantage Magnesium dry to raise my Mg. After reading the directions it seemed like I would need a ridiculous amount of this stuff to raise my Mg to 1300. So I checked out the calculator it says 89 tsps to raise 70G of water to 1300. Is this correct? Is there a better product to use? If this is correct and the right product to use what is the best method to add it. Drip? all at once?

Thanks,
Steve

[Shooter7]

Hi fly,

Here's a magnesium article by Randy Holmes-Farley. It talks at length about Mg and its role in seawater, as well as supplementing marine aquariums:

http://www.advancedaquarist.com/issues/oct2003/chem.htm


It's good to read the whole article, but for some of the stuff you're asking regarding how much you need to add and how you should be adding it, pay particular attention to the section titled:

"Supplements for Magnesium in Marine Aquaria"


HTH :cool:

[superfirefly]

Thanks Shooter. I will give it a read and post if I have any other questions.

[ScruffyRubicon]

It really depends on where you keep your calcium and alk. Check out this site:

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

You can play with the numbers to get them where you want them. It will give you the numbers you need to balance the system.

I keep my alk at 9.6 dkH. Balanced calcium at that level should be 430. Mg should be 3 times your calcium level. That puts my Mg level at 1290.

[DrBDC]

Anywhere from 1300-1500 is a good target. Being just a bit above NSW can help so that it doesn't fall below NSW levels as it's used up. Just like keeping alk slilghtly above 7, it's a "buffer zone". Not to confuse with what we commonly call a buffer.

Some are using 1500+ levels and having sucess with bryopsis but that's another topic. There is quite a large safe range for mag.

Yes it can get expensive to correct a deficiency of 100+. I'd look at that article linked above and it sounds like you already did use the calculator linked by Scruffy.

The main ingredient that you want to use is MgCl (magnesium chloride). You could also try to use a magnesium sulphate but I would limit that to an increase of about 50 per water change. So you can get in a good range in about 2-3 water changes. The problem with using the sulphate based mag supplements is that it can skew your sulphate balance. Some of the commercial mag supplements are sulphate based which is just epsom salts with a fancy price tag. You need to read on the ingredients and see if they are a scam. Kent's tech-M is a good one I know.

[superfirefly]

Thanks for the help everyone. I use instant ocean for water changes. I will test it for Mg before my next change but off the top of your head does anyone know if it is high or low. I am going to assume low since my Mg was low.

[Shooter7]

Mine always registered low when I used IO. I switched to Reef Crystals a few months back and this helped with the MG levels. I've also used epsom salts to help boost Mg in the past when I've needed a quick bump.

[DrBDC]

You need to bump IO about 75 on calcium and about 150 of magnesium. This small amount can easily be done with just epsom and even the new versions of dowflake or prestone driveway heat. Statistically the new versions of those won't make a difference in the balance. For large adjustments in ca to the whole tank, don't use the new dow chemical products though.

[superfirefly]

150 in magnesium? Wow I do 20 gallon weekly to biweekly water changes, that is going to get expensive to dose. Reef Crystals it is.

[JxMetal]

Screw any aquaria marketed magnesium buffer. Go get the 4 lbs. box of epsom salts and dose from there. It's like $5. I have my magnesium around 1100 and used almost 3 pounds to get it up to about 1500. Obviously I did this over a two day span.

[tbrill]

you need to look at www.twopartsolution.com

it will also help you get a grip on keeping your alk/calc in line and save you money!!