Why does Mag fluctuate?

[jkobel]

Ive been using the Trident for the last month and loving it.

I have been curious as to why the Magnesium fluctuates like in the this image. I have not added Mag in a couple months so why is it fluctuating let alone just going up like this?

If this were Alk or Ca I would understand because I'm adding daily so its testing when consumption is low so there is excess in the water. But since I'm not adding Mag, why isn't it just consistently going down?

Follow up question - How often are you all adding Mag? In the past I have added 1-2 times a year (because thats about when I would test for it) but now with all this data, how important is it really to keep it a certain level.

To clarify, i'm not worried about a specific number, but if there is best practice here that helps my corals be more healthy and grow faster by aiding in Ca uptake I'm interested.

Thx

 

[MnFish1]

Ive been using the Trident for the last month and loving it.

I have been curious as to why the Magnesium fluctuates like in the this image. I have not added Mag in a couple months so why is it fluctuating let alone just going up like this?

If this were Alk or Ca I would understand because I'm adding daily so its testing when consumption is low so there is excess in the water. But since I'm not adding Mag, why isn't it just consistently going down?

Follow up question - How often are you all adding Mag? In the past I have added 1-2 times a year (because thats about when I would test for it) but now with all this data, how important is it really to keep it a certain level.

To clarify, i'm not worried about a specific number, but if there is best practice here that helps my corals be more healthy and grow faster by aiding in Ca uptake I'm interested.

Thx

1. the measurements (for whatever reason are incorrect)
2. If correct 1330 -1360 is a non-issue. I can't read the numbers on the bottom of the graph - if that is during a day - it suggests an error in testing. EDIT - I just saw that most measures are daily on the graph.

HOWEVER, the measurement error for Mg is 15PPM + or - - thus most of your measurements are within the error of the device.

 

[jkobel]

1. the measurements (for whatever reason are incorrect)
2. If correct 1330 -1360 is a non-issue. I can't read the numbers on the bottom of the graph - if that is during a day - it suggests an error in testing. EDIT - I just saw that most measures are daily on the graph.

HOWEVER, the measurement error for Mg is 15PPM + or - - thus most of your measurements are within the error of the device.

Correct, this is measuring 2 times a day, 12am/pm. So you're thinking this is largely showing the margin of error?

 

[OctaviusBrine]

Mine is all over the place as well. I check against my Hanna every now and then and it’s never right I swear. I calibrate it regularly and never helps. I don’t trust it. I’ve had mine running for over a year now. Alk sways as the bottle gets low calcium stays pretty solid.

 

[mook1178]

Yes. if your tank is 1340 then you can expect readings +/- 15 of that, so 1325-1355.

 

[Reefer Matt]

That’s a difference of 15-20 ppm. Very close to margin of error for the Trident, and normal. Also, is your salinity changing? It shows a trend of possibly not being topped off completely. Are the other parameters showing that upward trend?

 

[MnFish1]

Correct, this is measuring 2 times a day, 12am/pm. So you're thinking this is largely showing the margin of error?

Don't know - but it looks that way - if it keeps trending up (which it kind of is) I would think about calling tech support - you could always buy a Mg test you could do at home to verify.

 

[jkobel]

That’s a difference of 15-20 ppm. Very close to margin of error for the Trident, and normal. Also, is your salinity changing? It shows a trend of possibly not being topped off completely. Are the other parameters showing that upward trend?

This is a good question and the first thing I checked as I did run into that a couple weeks ago but no, in this case, water level is normal

 

[Randy Holmes-Farley]

The only way magnesium actually fluctuates is by salinity fluctuation.

Note that it doesn’t take much. Sg from 1.0260 to 1.0263 will boost magnesium by 15 ppm.

 

[MnFish1]

The only way magnesium actually fluctuates is by salinity fluctuation.

Note that it doesn’t take much. Sg from 1.0260 to 1.0263 will boost magnesium by 15 ppm.

Curious - do you agree his pattern is within the error range posted on the Trident site - or indicates an upward trend? (again assuming the trident is funtioning normally) - EDIT - And BTW - a clinically insignificant rise if it does not continue.

 

[Randy Holmes-Farley]

Curious - do you agree his pattern is within the error range posted on the Trident site - or indicates an upward trend? (again assuming the trident is funtioning normally) - EDIT - And BTW - a clinically insignificant rise if it does not continue.

Claiming a precision of 15 ppm is meaningless, and that’s all I saw. Maybe they do not even understand what the word means. It would imply that it cannot even provide answers closer together than 15 ppm, but says nothing about accuracy.

 

[MnFish1]

Claiming a precision of 15 ppm is meaningless, and that’s all I saw. Maybe they do not even understand what the word means. It would imply that it cannot even provide answers closer together than 15 ppm, but says nothing about accuracy.

I can't remember the exact wording - but you answered the question!

 

[taricha]

To say the same thing as others a different way....
If I was using a Mg test that gave me 1345 +-15ppm repeatedly day after day, I'd be very happy and conclude that both my Mg was stable, and that my test kit is very repeatable (+-1% repeatability is hard to beat in any context in reef testing)