Calcium and Magnesium Dosing

[MUTiger]

I have a Red Sea Reefer 250. I currently have a Red Sea ReefDose2 which has only 2 dosing heads and thus only allows 2 supplements to be dosed. I am currently dosing calcium and alkalinity, but would also like to begin dosing magnesium. Has anyone tried to mix the Red Sea Calcium and Magnesium supplements in the correct ratio to allow dosing both supplements with one doser? I asked Red Sea this question and they gave the typical “We have no experience with this and would not recommend it” response.

 

[*GAREEF*]

I have a Red Sea Reefer 250. I currently have a Red Sea ReefDose2 which has only 2 dosing heads and thus only allows 2 supplements to be dosed. I am currently dosing calcium and alkalinity, but would also like to begin dosing magnesium. Has anyone tried to mix the Red Sea Calcium and Magnesium supplements in the correct ratio to allow dosing both supplements with one doser? I asked Red Sea this question and they gave the typical “We have no experience with this and would not recommend it” response.

Is the tank loaded with corals?
I use a two part B- ionic, it has a little magnesium in the calcium portion but other than that I rarely have to add magnesium unless I have a tank packed with larger colonies of sps.

 

[Randy Holmes-Farley Verified Community Expert]

The magnesium portion may have a lot of sulfate in it, which if so, will precipitate if put into a calcium supplement.

 

[MUTiger]

Is the tank loaded with corals?
I use a two part B- ionic, it has a little magnesium in the calcium portion but other than that I rarely have to add magnesium unless I have a tank packed with larger colonies of sps.

A mixed reef with a lot of LPS and a few SPS. Would like to add more SPS.
Magnesium has been running around 1200 and I would like to get it up to 1300-1350.

 

[*GAREEF*]

A mixed reef with a lot of LPS and a few SPS. Would like to add more SPS.
Magnesium has been running around 1200 and I would like to get it up to 1300-1350.

How are you checking the magnesium?
I have yet to find an accurate test outside of icp ms testing.

 

[MUTiger]

The magnesium portion may have a lot of sulfate in it, which if so, will precipitate if put into a calcium supplement.

I would imagine that if the magnesium supplement had sulfate in it that it would also precipitate as magnesium sulfate.

 

[MUTiger]

How are you checking the magnesium?
I have yet to find an accurate test outside of icp ms testing.

I have been using both a Saliferttest kit and a Red Sea test kit.

 

[*GAREEF*]

I have been using both a Saliferttest kit and a Red Sea test kit.

Yes I’ve compared both of those and Hanna checker with my icp ms test and they were all off by 100- 300. I constantly got different results from all three that’s why I’ve compared them with icp Ms. Now I don’t even check my mag but on my icp I’m always in a good range.

 

[Randy Holmes-Farley Verified Community Expert]

I would imagine that if the magnesium supplement had sulfate in it that it would also precipitate as magnesium sulfate.

Magnesium sulfate is extremely soluble. Calcium sulfate is not, and that fact is a critical design element in making two and three part systems.