Poll: Magnesium Level

[afternoondelight]

I shoot for 1400. Do daily automatic water changes (Instant Ocean Reef Crystals mixed to 1.026) that add up to 10% volume per week.

Dose Magnesium (20mg per day)
Alkalinity (16mg per day)
Not currently dosing Calcium but will probably need to as all my acros and other SPS as well as a veritable crap ton of LPS are all really taking off.

Do four daily auto testing with the Trident (and regular manual back-up testing) and the past couple months my numbers have been solid and consistent with a little tweaking here and there.

This morning's numbers were:
Allk 8.4
Calcium 455
Magnesium 1455

 

[Randy Holmes-Farley]

Dose Magnesium (20mg per day)
Alkalinity (16mg per day)
Not currently dosing Calcium but will probably need to as all my acros and other SPS as well as a veritable crap ton of LPS are all really taking off.

That dosing seems incredibly high for magnesium relative to alk and calcium, unless you are offsetting a low mag salt mix. Your current numbers seem to reflect it, though they may not be accurate.

There's no way that ratio matches consumption. Real consumption ratios are more like 2.8 dKH of alk, 18-20 ppm for calcium, and 0-2 ppm for magnesium.

I'd look into not measuring magnesium at all since testing can be rather inaccurate:

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

 

[CHSUB]

Don’t test, don’t care. Add a small amount to ATO water and weekly WC to maintain.

 

[theMeat]

Don’t test, don’t care. Add a small amount to ATO water and weekly WC to maintain.

My thinking is if you don’t test for it don’t add it

 

[theMeat]

Is it still believed that refugiums and algea scrubbers increase mag consumption?

 

[CHSUB]

My thinking is if you don’t test for it don’t add it

Add an amount based on Alk addition. Add plenty of stuff I can’t test for, however I do eye test daily and it always passes with current maintenance and additions.

 

[theMeat]

Add an amount based on Alk addition. Add plenty of stuff I can’t test for, however I do eye test daily and it always passes with current maintenance and additions.

Well, the good part about adding mag without testing is you can go pretty high without issue

 

[CHSUB]

Well, the good part about adding mag without testing is you can go pretty high without issue

Icp test had it at 1251, not that I cared.

 

[afternoondelight]

That dosing seems incredibly high for magnesium relative to alk and calcium, unless you are offsetting a low mag salt mix. Your current numbers seem to reflect it, though they may not be accurate.

There's no way that ratio matches consumption. Real consumption ratios are more like 2.8 dKH of alk, 18-20 ppm for calcium, and 0-2 ppm for magnesium.

I'd look into not measuring magnesium at all since testing can be rather inaccurate:

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

I respect you Randy and will by all means check, but as I said I test 4X daily with the Trident and also back up with Salifert. Not sure what is bringing my Mag numbers down, but until I started dosing they were chronically low (in the 1200's). Thanks for the input and I will dig some more into what's going on.

As an aside, my NO3 is always low (.5-3) and without a PhosBan reactor my PO4 is chronically high (.20-.26).

I run a refugium and am careful NOT to over feed so not sure how that ratio keeps staying steady. I am dosing nitrates to try and bring the NO3 up to around (5-10) and keep the phosphates around .08.

Am I wrong to shoot for these numbers? I am striving for consistency vs a certain number. I am in my 9th month of this mixed reef tank and feel like things are as stable as they have been, which probably means the wheels are about to fall off...lol.

Hope not

 

[Randy Holmes-Farley]

I respect you Randy and will by all means check, but as I said I test 4X daily with the Trident and also back up with Salifert. Not sure what is bringing my Mag numbers down, but until I started dosing they were chronically low (in the 1200's). Thanks for the input and I will dig some more into what's going on.

As an aside, my NO3 is always low (.5-3) and without a PhosBan reactor my PO4 is chronically high (.20-.26).

I run a refugium and am careful NOT to over feed so not sure how that ratio keeps staying steady. I am dosing nitrates to try and bring the NO3 up to around (5-10) and keep the phosphates around .08.

Am I wrong to shoot for these numbers? I am striving for consistency vs a certain number. I am in my 9th month of this mixed reef tank and feel like things are as stable as they have been, which probably means the wheels are about to fall off...lol.

Hope not

1400 ppm seems a high target to me, but that’s opinion. You are already above your target, assuming your kit is accurate.

Two things that are not opinion is that magnesium cannot be significantly consumed when calcium is not, and that magnesium test kits give inaccurate answers in a reasonably high fraction of cases.