balanced mag calc?

Benny Z

In Memoriam
is there a calculator that shows the balanced magnesium level for a given alkalinity level? got a link?

thanks!
- ben
 
in the post above you: :)
Reef Chemistry Articles
The first two posts in this thread are lists of some of my articles that relate to reef tank chemistry. In the next few posts are some of the articles published by others on reef chemistry issues.

Handy Calculators (I don't claim to have written these, but they are very useful)

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

Calcium Reactor setup calculator (CaCO3/CO2 reactors)
http://home.comcast.net/~jdieck1/reactor.html
 
thanks, but those calcs don't tell what the balanced level of magnesium is...they just tell you how much product to add to get to a set magnesium level given water volume and starting mag level.

what i'm looking for is something that will tell me given "x" dkh, i should have "y" ppm of magnesium, similar to the way those calcs tell you the balanced level of calcium for "x" dkh.
 
Is there a correlation between magnesium and alk---I think that mag is not included in a dKh measurement
correct me if i am wrong?
 
There really isn't any useful concept of balance between alkalinity, calcium, or magnesium. The "balance" portion of the calculator is not useful and makes some bad recommendations. As long as the parameters are in the acceptable range, the tank should be fine.
 
<a href=showthread.php?s=&postid=10617973#post10617973 target=_blank>Originally posted</a> by Benny Z
hmmmmmmmm............

my mother used to say that to me when she had another agenda in mind :) care to elaborate further?
 
no, not really, it's just interesting to me.

i've always known that we should aim for 1250-1350 ppm mag, but thought there was a "perfect" balanced level, chemically, based on sg, alk, & calc. obviously we have a "perfect" balanced level of calc to alk...thought there was a direct tie to magnesium.

like, for an sg of 1.026, with a system set to 9dkh, the balanced calcium level is 425ppm and the "perfectly balanced magnesium level" is 1295.

obviously that was an incorrect theory.
 
There's a lot of threads on the "balance" issue, if you want to do some reading. It's not really a useful concept for these parameters. I don't know where that started. Keeping the major ions (sodium, chloride, sulfate, etc) in rough balance is a good idea, but trying to compute a formula for precise levels of alkalinity, calcium, and magnesium is going too far, in my opinion.
 
<a href=showthread.php?s=&postid=10617814#post10617814 target=_blank>Originally posted</a> by bertoni
There really isn't any useful concept of balance between alkalinity, calcium, or magnesium. The "balance" portion of the calculator is not useful and makes some bad recommendations. As long as the parameters are in the acceptable range, the tank should be fine.

I agree the calculator is not correct on the balanced range but is close at "normal" levels. If you want to see what we're talking about try putting in 90ppm calcium and raise it to 100ppm and see what it tells you your Alk should be at (negative number).

Forgetting about the calculator.

Alk, Ca & Mg are all tied together pretty tightly. If one get's to far out of balance the other two have problems. Typically due to water changes the Mg stays at a decent level that doesn't cause problems so people tend to "forget" or think it does't matter. But if it gets to far out of balance from the others from an ionic standpoint we get precipitation and/or Alk levels that we can't keep up.

I think you can safely look at it two ways. One way is just keep levels of these 3 items in a "proper range" like:
Alkalinity: 8-11dKH
Calcium: 380-440
Magnesium: 1250-1350

If you can keep them these 3 items in that zone they are relatively balanced enough to never matter and you shouldn't experience any problems.

However, if one of them gets out of whack bad enough to cause precipitation then you really need to solve the ionic balance or you can go round and round with dosing and precip, dosing and precip in what seems like a never ending battle.

So there really is a balance of these but no "concrete" numbers per say. I say this because if you try and match NSW exactly with a formula then you'll run differently then most of our tanks.

Almost everyone runs Magnesium at close to NSW, Calcium a little higher then NSW and Alkalinity a LOT higher then NSW. Running higher then NSW (380ppm) levels of Calcium gives us some lead way on the levels while guaranteeing we have enough calcium in the tank. Alkalinity is normally ran a lot higher by most people because over the years we've found that higher levels of alkalinity tend to help with calcification.

So in a sense we have "artificially" changed the ratios from NSW for our tanks because it's been proven to work better in our enclosed environments and gives us more lead-way on target values. This makes it hard to follow NSW ionic balances. :)

Here's the "method" I use and teach my customers. Target 420 for calcium, 10 dKH for Alkalinity and 1300 for Magnesium. These are pretty much middle ground numbers and have a safety margin on each side. (little bit to much dose, not quite enough, test kit off a little, etc). I prefer to aim for the middle instead of "pushing" a value. While these are not ideally NSW balanced they are good "tank" balanced numbers proven over the years to yield good results.

I think it's pretty easy to measure/test each of these three items and make dosage adjustment (online calc good for this) to get the levels in check. What I think causes a lot of people problems is water changes.

Typically most salts don't mix up to the "ratios" we run our tanks at.

For example our tanks (values above) broken down:
1dKH Alk, 42ppm Ca, 130ppm Mg

Now take a bucket of salt mixed up and it might come out to:
360 Ca
11 dKH Alk
1250 Mg
1dKH Alk, 32.7ppm Ca, 113.6ppm Mg

As you can see this is out of balance with our intended goals as can be seen from the breakdown above. To keep our tank ionic balance you would want to dose the Ca & Mg to bring the levels up on your mixed water before doing the water change. - alternately do water change, wait 1 day, test these levels and adjust back to normal.

Honestly I think the biggest problems occur from water changes where the water doesn't match intended tank "ratios" and from arbitrary doses of "additives" without testing and proper/specific dosages.

The good part about kalk drips, Ca reactors and 2 parts is that they typically add back in the same ionic balanced parts of Ca & Alk that typically calcification uses.

So overall I agree with bertoni in that trying to worry about balanced levels isn't important. Shoot for the middle of the proper ranges and don't struggle with it. Use a "balanced" method of adding Ca/Alk if you can to replenish them on a daily or semi-daily basis and just enjoy the tank.

Carlo

PS if using separate products like Turbo Calcium and Baking Soda work for you then great but don't worry about trying to make sure you always add the "same amount" of each at all times. It's far better to just concentrate on staying in the proper ranges.
 
If you define "keeping the balance" as keeping all the parameters in their recommended ranges, as with a balanced additive, that's fine. However, trying to tie an alkalinity of 3.25 meq/L to, say, 375 ppm calcium, I think that's unreasonable.
 
Not saying right or wrong but why unreasonable?
I'm not even saying that would be the correct "ionic balance" cause I'm feeling to lazy to do the math but assuming it is the correct ionic balance why would it be unreasonable?

Just curious but do you think using 2 parts solutions (or really 3 part if you include the Mg) or using Kalk drips or Ca reactors (all balanced) is unreasonable?

Just curious why you think it's unreasonable to keep the levels in check with each other regardless of lower then normal, normal or higher then normal recommended levels? At least when they are balanced with each other you don't get into the "funk" zone where one gets depressed and causes problems getting the tank back in balance.

Carlo
 
I don't see any logic to tying the parameters that precisely to each other. Some people run 7 dKH and high calcium levels, perhaps 400 ppm, because higher alkalinity levels seem to cause SPS problems. I run 10-11 dKH and 400 ppm calcium to give some room for missing a day's worth of supplements. Both approaches seem reasonable to me.
 
"Playing devil's advocate" but you are keeping them balanced only you are doing it in the tank.

What's so wrong with making sure they are roughly "pre-matched" in the container before doing a water change?

Seems pretty logical to me.

BTW, I wasn't saying at all that "one size fits all". I was saying take the "normal" levels you run in the tank and use those values to figure out your "optimal" balance dKH to Ca to Mg wise. This way you are always in close proportion when every you add new salt water to the tank. Regardless of high or low amounts it's always in proportion this way and you risk little chance (unless extremely high) of getting precipitation or depressed Alk levels.

It's actually not a big deal. Heck if you premix your salt and use the same type of salt all the time you can figure this out pretty easily and know to add 2 teaspoons of this and 1 teaspoon of that (type thing) to the mix container.

Carlo

PS Honestly this is just another way of doing it. As long as you test the tank and adjust back to the target zones on each of these elements you'll be fine. Whatever works for each person is the "best" as long as it's done.
 
The original question was about a formula that tied calcium, alkalinity, and magnesium to "correct" levels. I don't think that such a formula exists in any useful sense.
 
<a href=showthread.php?s=&postid=10638312#post10638312 target=_blank>Originally posted</a> by bertoni
The original question was about a formula that tied calcium, alkalinity, and magnesium to "correct" levels. I don't think that such a formula exists in any useful sense.

For normal reef value (not NSW):
1dKH Alk, 42ppm Ca, 130ppm Mg
1/42/130

Carlo
 
I've never seen any useful logic or reasoning behind equations like that. I can see a number of reasons to ignore them.
 
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