Dosing Mg everyday!!! More than Alk or Ca

[Kamper]

I have a mixed reef 180 total gallons
I’m dosing 30ml-40ml per day of Mg to keep it at
Mg-1250 dosing by hand 30-40ml a day
Alk-9.3 Dosing 20ml per day dosing pump
Ca-420 Dosing 20ml per day dosing

Any one else dose this much Mg?
Thinking of getting another dosing pump for Mg. It’s been this way for 10 month

 

[Spare time]

Magnesium supplements are not very concentrated (meaning I could put cups in without a problem but that with alk or calcium would be way too far over). However, a daily dose of magnesium is sort of surprising to dose magnesium daily unless you have a packed sps reef.

 

[Susan Edwards]

I have a bit of trouble keeping mg over 1300 and find I too have to dose heavier

 

[Randy Holmes-Farley Verified Community Expert]

What exactly are you all dosing?

There is no possible way for magnesium consumption to be more than about 1/10th of the calcium consumption in ppm per day, since they are always used together. Anything much higher is test error. Real demand is on the order of 0-2 ppm magnesium daily.

 

[Mical]

My money is on bad test...

 

[lion king]

Yes it is likely testing error, mg is usually very stable and needs minimal adjustments.

 

[Kamper]

It’s not a bad test
I’ve used 2 - different test kits and use Salifert
I wouldn’t put money on a bad test
Been in this hobby for 25 years
Will try another test kit but think something else is going on

 

[Susan Edwards]

my mg test 10/18 was 1290. This week, fell to 1170. It varies between 1160 and 1290.
10/25
ca 380
alk 8
mg 1280
po4 .36 (down from 1.43 in september)
no3 40-80 (down from over 160)

plan to dose (manually until I get doser going)
ca 40 day
alk 20 day
mg 80 day

 

[Randy Holmes-Farley Verified Community Expert]

my mg test 10/18 was 1290. This week, fell to 1170. It varies between 1160 and 1290.
10/25
ca 380
alk 8
mg 1280
po4 .36 (down from 1.43 in september)
no3 40-80 (down from over 160)

plan to dose (manually until I get doser going)
ca 40 day
alk 20 day
mg 80 day

Unless your salinity is varying significantly, that range is test error, not real variation. Magnesium cannot drop 120 ppm in a week.

 

[Randy Holmes-Farley Verified Community Expert]

It’s not a bad test
I’ve used 2 - different test kits and use Salifert
I wouldn’t put money on a bad test
Been in this hobby for 25 years
Will try another test kit but think something else is going on

Can you answer the question about what products you are dosing in post #1?

 

[Kamper]

Can you answer the question about what products you are dosing in post #1?

ESV mag

 

[Kamper]

Both test kits (Salifert) test the same.

 

[Susan Edwards]

I believe I use the salifert too. Also ESV CA, Alk, Mag

 

[Kamper]

My salinity is spot on 1.026
I have it hooked up to an ATO so the salinity is not an issue.
im scratching my head. I appreciate the feedback but I have to believe the results of my 2 kits. Also my Ca and Alk are pretty stable with dosing 20ml per day which is keeping my Ca at 420 and Alk at 9.3
I would think if I was over dosing my Mg, Ca and Alk would swing. But they are very stable and all corals are doing well

 

[schuby]

And you're dosing ESV Bionic 2-part for Alk and Calcium?

 

[Kamper]

Yes using all ESV products for Ca, Alk and Mg

 

[Randy Holmes-Farley Verified Community Expert]

Yes using all ESV products for Ca, Alk and Mg

Assuming that you are using normal ESV-B-ionic and not ESV Bicarbonate two part, then your demand is VERY LOW for calcium and alk. Only 0.22 dKH per day and 1.8 ppm calcium per day. if you are using the bicarbonate version, it is even lower, at half that amount. This also assumes you diluted them properly if you bought the concentrate form.

Note that the calcium part of B-ionic contains magnesium, and generally you should not need any more, at least in the short term.

Assuming the ESV magnesium product was not messed up somehow, then on top of the magnesium added with the calcium part, you are adding an additional 2 ppm of magnesium per day.

That is really not much magnesium (although much more than is being consumed), and it would take a long time to accurately detect that addition with a kit. Certainly, in a week you will still be within the error of any hobby kits.

As a final comment, even a tiny change in salinity will cause the magnesium to change much more than you are adding in a day. 35 ppt seawater, 1280 ppm magnesium, at a sg of 1.0264 changing to a sg of 1.0262 will have dropped magneisum by 10 ppm.

So my belief is that you are adding so little of any of these additives that you cannot accurately measure the changes in calcium and magnesium, and minor changes in salinity will swamp out the mag additions for anything except long term measurements.

 

[nereefpat]

It’s not a bad test

It's not that the test is bad, it's just that the result is within the margin of error for the kit.

 

[Kamper]

Thank you very much Randy
I agree on all your points
One test I haven’t done is to test the water before and after adding Mg to see if there is an increase after adding Mg. I’m wondering if the ESV. B-ionic was diluted by myself or the manufacturer. I’ve never added this much Mg in my 25 years which tells me that something is not right and some detective work needs to be done.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you very much Randy
I agree on all your points
One test I haven’t done is to test the water before and after adding Mg to see if there is an increase after adding Mg. I’m wondering if the ESV. B-ionic was diluted by myself or the manufacturer. I’ve never added this much Mg in my 25 years which tells me that something is not right and some detective work needs to be done.

Sounds good.

You'll need to add a lot at once to see it.

Let us know what you find. :)