replenishing magnesium
 

Just curious to what product everyone is using to replenish magnesium in their reefs? Powder or liguid and why? thx.

I use Kent's Tech-M Magnesium and buy at least two of the big jugs from J&L when ordering dry goods so I don't run out. I drip kalk in all three of our reefs, which helps sustain Ca and alk levels, but does nothing for Mg levels. Sure use a lot of the stuff :eek: Anyway, it's a liquid and easy to measure with a 10 ml plastic syringe from the drug store. Make sure to shake liquid Mg thoroughly while using as the heavier particles settle out quickly.

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I have the crystal form that I add to top up water when levels drop. They take a long time to disolve which sucks but they are cheeper. I think mine are Sea Chem.

Mg
 

Does everyone supplement magnesium or just some?

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Everyone should make sure their mag. levels are good. I'm sure Bev can supply the links as to why. :biggrin: Get your reading glasses ready!

Hope you have a few hours to kill... :mrgreen:
Good stuff though!

OMGosh, here come the Reef Chemistry links :biggrin: :

Aquarium System Volume Calculator:

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

The Reef Chemistry Calculator:

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

Reef Aquarium Water Parameters:

http://reefkeeping.com/issues/2004-05/rhf/index.htm

Magnesium in Reef Aquaria:

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

Solving Calcium and Alkalinity Problems:

http://www.advancedaquarist.com/issues/nov2002/chem.htm

High pH: Causes and Cures:

http://reefkeeping.com/issues/2005-03/rhf/index.htm

Low pH: Causes and Cures:

http://www.reefkeeping.com/issues/2004-09/rhf/index.htm

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You're slippin' Bev, that took a while. :lol:

Hey, I was napping, but answered as soon as I was awake enough to read my mail :biggrin: :razz:

Or you could use epsom salts

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:

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Here's something interesting. I checked my levels last night and I got this:

Ca+ 450 ppm,
Mg 1220 ppm,
ALK 7.87 D-KH

I won't be adding any Ca+ because its a bit higher then I usually keep it. I may buffer a bit for ALK, but here's what I've noticed thats interesting. Growth in my corals has really slowed down in the past couple of weeks that my Ca+ has been high (oops). Tonight I'll add Mg to bring my levels back up to 1280-1300 ppm and see what happens. Incidently, its taken two weeks for my Ca+ to go from 485 to 450 ppm, probly as a result of lower Mg levels.

Another note: according to the calculator it will take 304 grams of Seachem Mg (60.8 tsps), and 346 Ml of Kents to achive the levels I want. That seems like a lot to me.

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Going way back in my notes for my 37g, I had 1185 ppm of Mg when I began testing. The calculator sugggested I add 321 ml of Kent's Tech-M Mg.

Don't know what you mean by "346 Ml of Kents". If it is some kind of buffer, remember when using the calculator, the calculator measures alk in meq/l, dKH and ppm. You have to select the right measurement from the three choices. Many times I have forgotten to select dKH instead of the default meq/l and ended up with a horrendous amount of buffer I had to add. Luckily I remembered to double check.

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Well Tech-M by Kent is the only option it gives you for Kent products. I believe that "ppm" is the only option it gives you for Mg calculations as well. That dosage just seems like a lot to me, though I don't have measuring cups in front of me right now for reference. :confused:

Ooooooohhh, now I know what you are talking about - two types of Mg supplement - one being Kent, the other Seachem :biggrin: Geez, some people are just naturally slow :razz: Don't know anything about Seachem's product, only Kent's.

Yes, Ca and Mg on that calculator are measured only in ppm, as you state. Alk has the three measurements from which to choose.

Danny, a couple of things to consider here:

1. Did you use the tank volume calculator using inside measurements for an accurate volume of your tank?

2. Don't dose the Mg supplement all in one day. Spread it out over 2-3 days. For instance, I use a 10 ml plastic syringe for dosing so I can record how much I dose at a given time. In my 37g (which has a volume of only 35.5g according the volume calculator), I add 30 ml at a time. I might dose every 1-4 hours throughout the day, depending on what my day is like.

3. Measure Mg at some point to while dosing to see if you are actually overdosing or on target.

4. Record all test results and how much of what you dose so you can go back and observe patterns of use of alk, Ca and Mg. I also record pH before and after dosing (for buffers), time of day, and occasionally nitrate.

Dang, that's more than a couple of things, now isn't it :lol: :razz:

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Yah, its a lot of work but thankfully I have a new log book for th is tank. I'm pretty sure my system volume is acurate to within 2 gallons, or a days evaporation. I'll adjust tonight and measure a couple hours after.

Steve, I know exactly what you're saying and thanks for the good analogy :biggrin:

I guess you could sort of compare what Mg is to Ca as KH (alk) is to pH as it acts as a buffer for the other.

But I guess what I'm wondering is, let's say I test my Mg and it's at a little lower than desired levels (e.g. 1000ppm), and I purchase something to bump it up to 1400, would I see a difference in my corals? Will I see better color, better growth? Or am I just making sure my Ca doesn't crash?

if you take it to say 1300, And keep your Ca down about 380 to 400 I feel you get better growth, is this to say if you do the same you will to? well maybe, or maybe not. I would bet all things being equal that you would dee a difference it may be small but I think there would be one. Also it is the same a a sick person, they may look fine on the outside but not inside. so theres another thing to think about sence so little is actualy knowen about coral helth.

Steve

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IMO you don't want to super load your tank with any one substance. Mg is a slowly depleting element in a reef, much more so than Ca and Alk etc. If you add too much Mg (which we know is needed to make Ca bio available) you run the risk of precipitating the access Mg with Ca+ in you system, and will cause your Ca levels to drop faster. This was noticed in my tank once as aragonite turning into rock. I don't believe it is harmful to your corals, but it is a waste. I would keep your Mg at the high end of normal, around 1350 ppm, at this level your corals can best optinimize Ca consumption at around 350 to 400 as stated above.

When my Mg levels are down I noitice less Ca consumption when testing, which coralates to less coral growth. Hope this helps

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[quote="danny zubot"]couple things, Mg doesn't make Ca "bio available" if you read the articles Bev have been posting every chance she gets :mrgreen: I believe there is one that explains how Mg works in great detail, if not ask and I will find it and post it. but for a short version Mg simply coats Ca to prevent other stuff from bonding to it and dropping it out of solution so with out the proper amount of Mg Ca will participate out of solution. I guess if you want to say that makes it Bio available in a round about way it could be but it is a very misleading statement.

Also normal Mg levels are 1300 to 1400 ppm so 1350 is dead middle. there have been some tests done on higher Mg levels and it becomes a mute point after the "normal" range and it will take a much higher level to cause harm as nothing will use Mg except for the Ca ions themselves, but having said this I don't want people just to dump indiscriminately to raise Mg, always measure and raise it no more than 200ppm / day or so.

Steve