Magnesium too high

[KVYA]

I tested my magnesium with a Red Sea test kit and it was at 1540ppm and I do not dose magnesium

 

[Lninwa]

Is your test kit expired?

 

[Bronc]

It happens. Mine goes up as well and I don't dose it either.

 

[KVYA]

Is your test kit expired?

Nope. I don't think so at least. I got it about 5 months ago and this is only my 3rd time testing magnesium

 

[Downbeach]

That Mg kit can be a little tricky to use, especially when adding the 5 drops of reagent A, and having to mix each drop for 15 seconds, while keeping track all the drops. Here is the demo:



Another possibility is your SG. If you're using a swing arm type hydrometer, or a non/mis calibrated measuring device, you may not be adding the correct amount of salt mix when making up your WC water, i.e. too much will give you high Ca, Alk, Mg, etc., numbers, while not enough will cause these number to be low.

 

[KVYA]

That Mg kit can be a little tricky to use, especially when adding the 5 drops of reagent A, and having to mix each drop for 15 seconds, while keeping track all the drops. Here is the demo:



Another possibility is your SG. If you're using a swing arm type hydrometer, or a non/mis calibrated measuring device, you may not be adding the correct amount of salt mix when making up your WC water, i.e. too much will give you high Ca, Alk, Mg, etc., numbers, while not enough will cause these number to be low.

I use a refractometer. My SG is at 1.0265 so that might be why. My calcium is at 425. Alk was at 7.8 on Thursday but is now at 8.3

 

[Downbeach]

What are you using to calibrate the refractometer? What are your Ca and Alk numbers in your freshly made WC water? Using what salt mix?

 

[nervousmonkey]

The Red Sea test kit for Mg is the worst one to use. The change from what is the actual value to going over with the color change can be two drops, so I'd get another test kit for Mg. That's what I had to do, got Salifert, and started seeing numbers that were close to real.