Query regarding salinity calcium and magnesium level

[Anirban]

@Randy Holmes-Farley My question is pretty specific. Some salt mix recommend mixes at 33 ppt and some 34ppt. Now, their QC sheet says at 33 ppt the amount of Calcium is 440ppm and Mg is 1380ppm. If someone mixes that salt to a salinity of 34 ppt or 35 ppt what should be the Ca and Mg level in that salt water. I knew that will increase but how much specifically? Can it go over more than 1500ppm for Mg and 500 ppm for Ca? Whats the way to calculate it?

 

[Randy Holmes-Farley Verified Community Expert]

Everything in a salt mix (aside from things not really "in it" like pH and ORP) will rise and fall linearly with the salinity.

So calcium at 410 ppm at 33 ppt salinity will rise to 35/33 x 410 = 1.06 x 410 = 435 ppm

 

[Anirban]

Everything in a salt mix (aside from things not really "in it" like pH and ORP) will rise and fall linearly with the salinity.

So calcium at 410 ppm at 33 ppt salinity will rise to 35/33 x 410 = 1.06 x 410 = 435 ppm

Thanks Randy for that quick reply. So, the relation will be linear ?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Randy for that quick reply. So, the relation will be linear ?

Yes, linear in salinity, but not in specific gravity as written.

It can be linear in specific gravity using the digits after the 1, so 1.026 vs 1.024 --> 26/24 = 1.083x rise in everything.

You're welcome and happy reefing.

 

[Anirban]

Thanks a lot..

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.