Quoted from halfway down the Magnesium link
http://www.advancedaquarist.com/issues/oct2003/chem.htm :

Mg
 

I guess I'll head to my LFS today and pick up some Mg then. Thanks Bev. What brand do you reccommend?

Jason,

To quote myself from an earlier post in this thread :biggrin: :

Thanks for the info Bev and Danny. Now does anyone one use the powder form for Seachem? According to the description, the Seachem is a little more concentrated and cheaper in price. I am wondering if it's quality is comparable to one another? Although the liquid is a little more convenient to dose....hmmm?? Choices... :mad:

I always thought Mag was necessary when you can't keep your calcium up to the desired levels. Upping your Mag also allows you to up your calcium.

Is there a need to add Mag when you can sustain good calcium levels and have good coraline growth? I just don't feel like blowing money on a test kit to find out after the first test that my levels are fine :neutral:

I am sort of with you on this theory. Most of the time I just go by feel and observe the condition of the corals and tank first and if they seem to be growing and maintaining good health then I wouldn't bother testing. In my case, growth has been stunt the last couple months so therefor I did some tests. In doing so, I found that both my Ca and Alk are well below normal with no apparent changes to the Calcium reactor production (media disolving rate is normal). This lead me to believe that my Magnesium is not up to par. Like many people, I've never encounter this problem before until now so hopefully adjusting the magnesium level will re-stablize things again.

I used to use my pH probe as well as general appearance of my corals as guides to what was going on chemically in my tank. After reading the articles posted, I began testing and recording alk, Ca and Mg, rather sporadically at first.

Everything was way off at first, so I used the tank volume calculator, using inside the tank measurements, to figure out the exact water volume in each of our three tanks. Then I began dosing in small amounts like the reef chemistry calculator suggested, keeping track of what I was dosing and how much.

I've gotten into the habit of testing, recording test results and adusting levels bi-weekly. Each tank has different uptakes of alk, Ca and Mg and it varies from each testing period what has to be adjusted. So, now, I just keep at it knowing that the living organisms are using these chemistry components at different rates, even though we keep up with weekly water changes and other tank maintenance.

Corals are doing noticeably better now compared to how they looked before I began paying attention to water chemistry. And I thought they were doing okay without testing :rolleyes:

to answer you both Mg is actually a very important part of the water make up, and it is good to see people finally starting to ask about it after I have been preaching its importance for over two years on here, :mrgreen: anyways new tanks are notorious for having low Mg, the main reason for this is that most salt mixes are low in Mg to start with. Mg is one of the more expensive ingredient to add to a mix and if 1000ppm or 1100ppm will hold 380ppm of Ca then thats all they will put in, some less.

So I always monitor my Mg for the first month and get it up to 1300 or 1400ppm then I will reduce testing to once a month to see if it is depleting or not. If you are using a Ca reactor or supplements you might not notice a drop.

As for why do we need it at a proper level if I can hold my Ca are a good level. Well its a balance game, to make a stupid analogy would you want to walk on a ledge 2" wide 6000 feet in the air or would you want to walk on a ledge 5 feet wide? in other words why ride that close to problems (depleted Ca, low Alk) when you can have it at a proper level and have a cushion area be for these things happen?

as for the blow money on a kit thing, you spend more money on most fish than you will on a test kit and a test kit is more important than any fish/coral ect as with out them how do we know what is going on in our tanks.

Steve

What Steve said :cool:

And read the freaking articles :exclaim: I've posted them a gazillion times :razz:

I found if one only uses kalk as there source of calcium, then magnesium levels need adjusing from time to time.

Running a co2 reactor, I found my levels always stayed around 1350ppm. Guess the dissolving media provided enough.

Also most two parts and additives like Seachems Reef Advantage Calcium, have enough magnesium to maintain levels.

FWIW, I am now using the magnesium advertised for sale on here by another aquarist. I mixed a 25g batch of Instant Ocean, following the same amounts he used in his 45g mix, but adjusted for my size and the levels for calcium and alk. were exact to what he said they would be, with no precipitate. As I dont have a new mag. kit yet, I assume those levels are exact also. :smile: