Magnesium testing

[jrill]

I'm confused about magnesium testing. Using Fritz salt. Started with the Red Sea kit, magnesium was off the chart. Many drops past syringe so over 1600ppm.
Had a ICP test done and Magnesium is 1350.
Ordered Salifert kit and it also tests at over 1500 which is also beyond a full syringe.
I had contacted Fritz after the tries with the Red Sea kit and they said that Red Sea Mag kits generally test high.
So, what gives.
Thanks.

 

[Ron Reefman]

Test kits, IMHO, all test kits are notoriously unreliable for specific readings. And the reliablity of testing is as much about using clean equipment and doing the test in the exact same way every time.

I've never used ICP or any other testing company, but I wouldn't put too much faith in them either, especially on a one off test.

Test kits are better used to show trends. First, a Mg level of 1300 to 1600 isn't an issue. Yes sea water is around 1250-1300, but the Mg level in your DT of 1600 is not doing any harm. Some reefers run Mg artificial high and even beyond 1600. So if the test kit says 1500 and a month later it's down to 1450, and a month later it's down to 1400, you see the trend and decide if you want to add Mg.

 

[jrill]

Test kits, IMHO, all test kits are notoriously unreliable for specific readings. And the reliablity of testing is as much about using clean equipment and doing the test in the exact same way every time.

I've never used ICP or any other testing company, but I wouldn't put too much faith in them either, especially on a one off test.

Test kits are better used to show trends. First, a Mg level of 1300 to 1600 isn't an issue. Yes sea water is around 1250-1300, but the Mg level in your DT of 1600 is not doing any harm. Some reefers run Mg artificial high and even beyond 1600. So if the test kit says 1500 and a month later it's down to 1450, and a month later it's down to 1400, you see the trend and decide if you want to add Mg.

Good advice. Thanks.

 

[SPR1968]

I threw my Red Sea Magnesium test away after it always read 1500+ and then a Triton icp showed it low at 1240. Coral growth had really slowed down as a result of the low levels.

Not only is it a pain to do the test and very tedious, it’s not accurate

Try the NYOS Magnesium. It’s very simple and came within about 5ppm of my icp test. Infact ease of use is no comparison.

 

[Randy Holmes-Farley Verified Community Expert]

Many folks have issues with the Red Sea magnesium kit. I’m not sure why.

 

[jrill]

Many folks have issues with the Red Sea magnesium kit. I’m not sure why.

Good to know. Thanks.