Reef Crystals Mixing Low in Magnesium

[BeanAnimal]

30 or so miles offshore. Otherwise you are dealing with runoff and freshwater inputs.

Far easier to save a sample next time you ICP.

Personally I wouldn’t worry about mag testing to any degree of accuracy or repeatability unless it tested at 500 or 2000.

 

[Euphylliaphyle]

30 or so miles offshore. Otherwise you are dealing with runoff and freshwater inputs.

Far easier to save a sample next time you ICP.

Personally I wouldn’t worry about mag testing to any degree of accuracy or repeatability unless it tested at 500 or 2000.

Thanks.

 

[winxp_man]

get a small bag of different salt and see if that show correctly with the Sali tester.

 

[Euphylliaphyle]

That will be perfect. Did you save any for future use? Magnesium in seawater is perfectly stable.

Mg test results from 3/30/2026 sampling:

My result*: 1,335 ppm
ICP result**: 1,390 mg/l

* Salifert titration
** Oceamo ICP

 

[Randy Holmes-Farley Verified Community Expert]

That’s pretty good agreement. Still, if one saw that same difference with the higher one being 1300 ppm, many folks would unnecessarily dose magnesium. Hence my generic recommend to not test magnesium.

 

[Euphylliaphyle]

That’s pretty good agreement. Still, if one saw that same difference with the higher one being 1300 ppm, many folks would unnecessarily dose magnesium. Hence my generic recommend to not test magnesium.

Yup. I saw that all the time in management decisions and technician decisions and financial decisions. People freak out when numbers cross decade or century marks. Y2K?