Impossible mag readings

[Koh23]

Hello all!

Really need help, before i stuck a needle in....well, something....

So,i tested ca,alk and mg, and i got readings

Ca:500
Alk:9
Mag:1660

I did some water change, after that, readings were:

Ca:480
Alk:9
Mag;1410

I didn't dose anything for a full week, only yesterday i put 20ml (that is dosage) of brightwell koral color, and 10ml of brightwell restor (got some poor looking sps, trying to save them)....

Today, i tested:

Ca: 450
Alk: 7
Mag: 1710 !!!!!

Test is aquaforrest, it is correct, i checked it with "calibration" solution. Other parameters are in range, temp is 27C, salinity 1026, no3:10, po4:<0,02. Topping of with rodi water, 0tds. Salt i use is aquaforest sea salt...

What in the world can cause mag levels to rise, without dosing anything? I feed with formula one and two flakes, some diy food, same as always, newer had such problem.

Only thing, not sure how relevant is, i feed with mussels, one every few days, just slice one, and throw in tank, tomorrow i pickup empty shell. Is it possible that mussel affect magnesium levels?

Other thing, i tried some brightwell sps and softies food, per instructions, didn't feed with that everyday.... Can i blame them for such magnesium rising?

Sorry, i know it's stupid....

 

[Lavey29]

Are you sure about your salinity? Maybe a second opinion test on the magnesium? Even though it may be elevated it shouldn't hurt anything and will come down with water changes.

 

[Koh23]

Well, dont know what to say...

I calibrate refractometer before each measurement, with salifert calibration fluid, and with ro water.

Salinity is spot on 1026....

Dont have option to check somewhere else, but i believe that test is correct, after water change mag dropped down.

Question is why it rises without dosing anything?

 

[Lavey29]

Well, dont know what to say...

I calibrate refractometer before each measurement, with salifert calibration fluid, and with ro water.

Salinity is spot on 1026....

Dont have option to check somewhere else, but i believe that test is correct, after water change mag dropped down.

Question is why it rises without dosing anything?

Not sure. Magnesium is fairly easy to manage because tanks don't use very much at all and water changes easily replenish what is used. I dose a small amount weekly into my tank because I'm doing water changes every 3 weeks now. I doubt the food you feed has any affect but perhaps some of those dosing mixtures you used added some.