Extremely Low Mag?

KosmicReef · Feb 16, 2021

I recently purchased a new Red Sea magnesium reef pro test kit and of course put it to use the moment I received it. The expiration date on the bottles state 3/23. So I know they’re “new”. However my test results don’t seem to make any sense to me and I’m wondering the test kit is bad... or? I’ve test kit before and have watched plenty videos on how to accurately use the kit. Never had this issue before. This a 90 gallon tank including sump.

Test results from today (16 Feb)
Ph 8.4
Amm 0
Nitrite 0
Nitrate 20 (we are working on fixing this)
Cal 480
Alk 12
Mag 100

Previous mag tests on prior days were
4 Feb 21 - 400
7 Feb 21 - 320
Water change
11 Feb 21 - 360

Anyone have any ideas?

Randy Holmes-Farley · Feb 17, 2021

The magnesium is not correct. none of them. Either there is a problem with the kit, or you are using it incorrectly *(or you have a salt mix that is among the worst ever made).

You might be using the kit backwards. That doesn't seem to be common with Red Sea, but it is with Salifert.

To have a very low value means only a small amount of titrant was added before getting to the color change. If you added a large amount, like close to a full syringe, that is high magnesium, not low.

What salt mix?