High magnesium

[Dustinba]

what would cause super high magnesium?

Tank is a biocube 32 about one month old with 40lbs live rock, 20lbs aragonite sand. I run chemi pure elite, purigen filter floss and chaeto.
I have a 4 stage RODI unit from BRS as well.

I do weekly 5gallon water changes every Thursday. Today after the WT I did my testing which is the following:
Ammonia: 0
No2: 0
No3: 50
Phos: .02
Calcium: 420
Alk: 10.4
Salinity: 1.026
PH: 8.0
Mag: at least 1600

I use Red Sea test kit for mag, calc and kh.
Everything else is salifert. PH is API.

Last week when I tested magnesium it was 1300. I do feed a little heavy with mysis and reefsnow, but would that cause mag to rise that much?

Should I do another big WT and retest?
Fish and the few corals I have, toadstool, frogspawn, zoas and Duncan all seem fine.

 

[Dustinba]

I actually may have found the problem. Going to retest now

 

[Dustinba]

New test was 1480. Still a little high

 

[burninreefer]

That’s ok. I run mine 1500-1550. Good rule of thumb, triple your your calcium number for mag. But I like my mag a bit higher. It will boost growth

 

[justmee]

High magnesium is not a problem for fish or corals, it actually helps your water from precipitation, your water will not evaporate that quickly.