Magnesium Uptake or bad test?

[GuppyHJD]

My magnesium dosing is 100ml a day (Using BRS Pharma Magnesium Mix). This seem high, based on my 25 ml of the Calcium solution. What should I be looking into?

 

[gbroadbridge]

My magnesium dosing is 100ml a day (Using BRS Pharma Magnesium Mix). This seem high, based on my 25 ml of the Calcium solution. What should I be looking into?

Test kit error :)

 

[bushdoc]

I am sensing testing error, but I am curious what Randy is going to say tomorrow morning.

 

[GuppyHJD]

I am using AquaForest test kit

 

[bushdoc]

Check reference solution included with a test. This will give you an some idea idea.

 

[Randy Holmes-Farley Verified Community Expert]

What are the values? Have you tested your salt mix?

 

[GuppyHJD]

What are the values? Have you tested your salt mix?

The tank is testing 1425 magn, 450 calcium.

I have not tested the salt mix (using Instant Ocean).
I used the reference solution and the bottle shows 1310 but the test showed 1500.

 

[gbroadbridge]

The tank is testing 1425 magn, 450 calcium.

I have not tested the salt mix (using Instant Ocean).
I used the reference solution and the bottle shows 1310 but the test showed 1500.

So, the reference is supposed to be 1310? And when you test with the kit it shows 1500?

Test with some freshly mixed salt water and tell us what the test results are.

 

[Randy Holmes-Farley Verified Community Expert]

The tank is testing 1425 magn, 450 calcium.

I have not tested the salt mix (using Instant Ocean).
I used the reference solution and the bottle shows 1310 but the test showed 1500.

I would recommend testing the new salt water and see if water changes are a significant factor in the demand.

Real magnesium consumption in ppm per day is not more than about 1/10th of the calcium consumption. They are always used in tandem.

 

[bushdoc]

The tank is testing 1425 magn, 450 calcium.

I have not tested the salt mix (using Instant Ocean).
I used the reference solution and the bottle shows 1310 but the test showed 1500.

I suspect that this is problem with the way most Magnesium tests are devised-I believe reference solution Mg level is like stated and I do believe test kit is probably OK. I had similar problems testing Mg, sometimes had to check twice to get result I thought to be more probable. I hope you have noticed that you suppose to add 5 drops of reagent A and 3 drops of reagent B.
As Randy said-your Magnesium consumption is a fraction of Ca/Alk, so I would dose magnesium based on those and possibly skip Mg testing. You could also test your water at LFS as after your heavy Mg dosing it might be bit off the charts now.

 

[RibbonFish]

Do you have any mangrove in your sump?

 

[Randy Holmes-Farley Verified Community Expert]

Do you have any mangrove in your sump?

I personally think the whole mangrove magnesium connection is insignificant in terms of magnesium content of the water, and is one of the hobbies unproven myths.

Mangrove leaves contain more calcium (and other ions, including potassium) than magnesium, both for R. mangle (a salt-excluding species) and L racemosa (a salt secreting species).

 

[GuppyHJD]

Do you have any mangrove in your sump?

No mangroves

 

[GuppyHJD]

I suspect that this is problem with the way most Magnesium tests are devised-I believe reference solution Mg level is like stated and I do believe test kit is probably OK. I had similar problems testing Mg, sometimes had to check twice to get result I thought to be more probable. I hope you have noticed that you suppose to add 5 drops of reagent A and 3 drops of reagent B.
As Randy said-your Magnesium consumption is a fraction of Ca/Alk, so I would dose magnesium based on those and possibly skip Mg testing. You could also test your water at LFS as after your heavy Mg dosing it might be bit off the charts now.

Yep - LFS testing is next on my list.
I have been doing the 5 drops of A and 3 drops of B.

 

[GuppyHJD]

I changed to a Salifert test kit...it is showing 1340. I dosed with Seachem IONS Magnesium (100 ml) and still testing 1350.

 

[gbroadbridge]

I changed to a Salifert test kit...it is showing 1340. I dosed with Seachem IONS Magnesium (100 ml) and still testing 1350.

There is nothing wrong with 1350.

I would stop testing :cool:

 

[Randy Holmes-Farley Verified Community Expert]

I changed to a Salifert test kit...it is showing 1340. I dosed with Seachem IONS Magnesium (100 ml) and still testing 1350.

I agree with the above post. If it is 1340 ppm, why dose anything? That level is perfect and is already above natural seawater at 35 ppt.