Raising magnesium too quickly

[Trailermann]

I got a poor batch of Fritz Pro salt that gives me a Mg level of 980 ppm (confirmed by two LFS stores). I want to raise the mixed saltwater but so instructions say to not raise more than 100 ppm daily. Is that for the health of a display tank, or does that apply to batch of new salt water?

 

[miPapareef]

The 100 ppm applies to your display tank. When you make a new batch of salt water adjusted to the correct level.

 

[Trailermann]

Did you mean "adjust it to the correct level"?

 

[Randy Holmes-Farley]

I got a poor batch of Fritz Pro salt that gives me a Mg level of 980 ppm (confirmed by two LFS stores). I want to raise the mixed saltwater but so instructions say to not raise more than 100 ppm daily. Is that for the health of a display tank, or does that apply to batch of new salt water?

The point is to not add too much magnesium at once because of impurities that might be in the magnesium additive, rather than the magnesium itself. If you intend massive water changes, then it may not be OK to boost the new salt water that much, but if you intend smaller (10-15%) water changes, then its fine to boost the salt mix all at once.

To a big extent it depends on the purity of the additive.

 

[Randy Holmes-Farley]

FWIW, I'm skeptical of the result. Fritz salt is very popular now and I think we'd have seen more reports of bad batches if there was one.

 

[Trailermann]

Yes, I am puzzled about the Fritz also. I have tried multiple test kits, had samples testing at two LFSs, RODI water from three different sources, cleaning the mixing barrels thoroughly, using brand new containers, carefully and very slowly adding the salt to heavily agitated water, testing the salt mix soon after finishing the mixing, and testing one and two days later. I have used 30, 5 and 1 gallon containers.

Here is the result of my last batch, not much different than my other five batches.
kH 5.8
Ca 250
Mg 960

I have talked with a very experienced LFS owner, as well as the Fritz expert, to no avail. Any thoughts on what I could be doing wrong?

 

[Ty Hamatake]

Following along, those numbers seem really low.

 

[Randy Holmes-Farley]

Yes, I am puzzled about the Fritz also. I have tried multiple test kits, had samples testing at two LFSs, RODI water from three different sources, cleaning the mixing barrels thoroughly, using brand new containers, carefully and very slowly adding the salt to heavily agitated water, testing the salt mix soon after finishing the mixing, and testing one and two days later. I have used 30, 5 and 1 gallon containers.

Here is the result of my last batch, not much different than my other five batches.
kH 5.8
Ca 250
Mg 960

I have talked with a very experienced LFS owner, as well as the Fritz expert, to no avail. Any thoughts on what I could be doing wrong?

Super low salinity?

Excessive separation of materials in the dry mix, and using part to make a nonuniform seawater?

 

[TangingOut]

With levels that low, I'd suspect low salinity.

 

[Trailermann]

With levels that low, I'd suspect low salinity.

Yes, good point, but I used two different refractometers, both calibrated with solution. Also, I the salinity checked at the LFS. Wht the heck, I will check it again.

 

[Trailermann]

Yes, good point, but I used two different refractometers, both calibrated with solution. Also, I the salinity checked at the LFS. Wht the heck, I will check it again.

And one more thing, how far off would the salinity have to be to give a calcium reading of 250?

 

[Trailermann]

The an

Super low salinity?

Excessive separation of materials in the dry mix, and using part to make a nonuniform seawater?

Yes, the problem was salinity. My calibration solution was bad, very bad. My water was actually 1.026! Thank you all for your help.

 

[TangingOut]

The an


Yes, the problem was salinity. My calibration solution was bad, very bad. My water was actually 1.026! Thank you all for your help.

Is 1.026 a typo? Because that's what most reefers prefer their salinity at.

 

[Trailermann]

Crymmenee, typo it was. The actual salinity was 1.017, and probably has been like that for many weeks.