Low Magnesium Salt Mixes

[ptrick21186]

So I've been scratching my head trying to figure out where my magnesium has been going the last week. Finally checked my salt mix (Instant Ocean reef Crystals) and properly mixed salt water at 1.025 only comes out to 1230ppm. I like to keep it around 1300ppm. So obviously the problem is is I'm lowering my mag every time I do a WC. So how should I do this then? Should I be measuring the mag levels of my new water, calculating the dosage to bring the level up to my tank level, then adding that into my new water before I add it to the tank? Seems to be the only logical way right?

 

[CK00020]

I boost the mag in my io to 1450 when mixing, cal to 450 also. What I’m saying is boost your new salt water

 

[Randy Holmes-Farley Verified Community Expert]

So I've been scratching my head trying to figure out where my magnesium has been going the last week. Finally checked my salt mix (Instant Ocean reef Crystals) and properly mixed salt water at 1.025 only comes out to 1230ppm. I like to keep it around 1300ppm. So obviously the problem is is I'm lowering my mag every time I do a WC. So how should I do this then? Should I be measuring the mag levels of my new water, calculating the dosage to bring the level up to my tank level, then adding that into my new water before I add it to the tank? Seems to be the only logical way right?

Just to be clear, that is not a low magnesium mix, even assuming your values are correct. At 35 ppt, that 1230 ppm magnesium becomes 1299 ppm, which is above the ocean average at that salinity.

I would just raise the salinity to 35 ppt (sg = 1.0264).

But, magnesium is also cheap and easy to raise if you want to keep a lower salinity. You can add it to the salt mix, or the tank.

 

[ptrick21186]

Just to be clear, that is not a low magnesium mix, even assuming your values are correct. At 35 ppt, that 1230 ppm magnesium becomes 1299 ppm, which is above the ocean average at that salinity.

I would just raise the salinity to 35 ppt (sg = 1.0264).

But, magnesium is also cheap and easy to raise if you want to keep a lower salinity. You can add it to the salt mix, or the tank.

I guess that makes sense when you put it that way