Low Mg

[jvandy]

I posted this on my build page as well. Quick background on tank. 120g been set up for 5-6yrs. Haven’t done anything to it for the past 1-1.5yrs. Just have a few crabs and snails along with a small patch of GSP and a shrinking Zia. I’ve been testing Cal, dkH, Mg so I can get back to adding coral however I’m having an issue with keeping my numbers up. I did dose 3 tablespoons of baking soda yesterday and did a 10% water change an hour before testing.

1/30. 2/5. 2/6
Cal - 410. 499. 438
dkH - 7.5. 7.7. 10.3
Mg - 1100. N/A. 840

 

[Randy Holmes-Farley Verified Community Expert]

Have you been adding calcium and alkalinity all along?

If not, the magnesium values are more likely error than real.

What is the salinity?

 

[jvandy]

I was dosing awhile ago but stopped. Salinity is 1.026

 

[Randy Holmes-Farley Verified Community Expert]

Then I'm very suspicious it is not really that low. It cannot just decline on its own.

 

[jvandy]

Then I'm very suspicious it is not really that low. It cannot just decline on its own.

I bought a new Salifert test and just tested and it was at 1350, so maybe my reagents went bad.