Ultra-high Magnesium

[Scottiemac]

My magnesium is off the charts. >1580 on Red Sea and apparently 1800 is the limit on Hanna. I thought it would drop on its own, yet it's been this way for three weeks.
The cause was the Dosetronic dumping 2500 ml over six days when it was supposed to dose only 760.

Sometimes my Hanna test will show 1780, but the next test it goes back up to 1800. I'm assuming that's just a variance in how I do the test.

It seems I'd have to replace way too much water to tackle this with a water change; what is another option?

I had been dosing 160 a day, so it really should have used all of that excess up by now.

 

[KrisReef]

Magnesium falls very very slowly. Could take a long time, much longer than an overfill of Alk or CA.

If you do try water changes, make sure you get a very low MG salt mix or else you will struggle trying to get it lower. It will fall with time, maybe just wait until Christmas and retest then?

 

[Reef.]

Any issues?

If not and you don’t want to do extra water changes, just reduce it slowly with your regular water changes.

 

[Randy Holmes-Farley Verified Community Expert]

Lethargic snails are sometimes reported when magnesium is very high. You have any snails?

 

[Scottiemac]

Any issues?

If not and you don’t want to do extra water changes, just reduce it slowly with your regular water changes.

Noticing a hardening of my substrate.

 

[Scottiemac]

Lethargic snails are sometimes reported when magnesium is very high. You have any snails?

Yes, but they don't seem particularly upset. The only thing I've noticed is my substrate is hardening in the lower flow areas. Just saw that this morning.

 

[Randy Holmes-Farley Verified Community Expert]

Noticing a hardening of my substrate.

I do not think that is a consequence of elevated magnesium. Magnesium tends to reduce the chances of calcium carbonate precipitation.

 

[Scottiemac]

It's been a couple of weeks and my magnesium is still over 1800 on the Hanna checker. I stopped with the Red Sea because I'm running out of reagent, but the other day it was still showing >1580 on the Mastertronic.

Could anything else be keeping my magnesium up? I've been adding about 25ml of Calcium every day and next to no Alkalinity.

I've ordered another bottle of Hanna reagent, but the one I have is several years before expiration.

 

[Randy Holmes-Farley Verified Community Expert]

Magnesium depletion is extremely slow. I do not know what 25 mL of calcium relates to in ppm of calcium added per day, but magnesium depletion is at least 10x slower, so to see a 50 ppm drop in magnesium may take a very extended period.

Did you test your new salt water?

 

[Scottiemac]

Magnesium depletion is extremely slow. I do not know what 25 mL of calcium relates to in ppm of calcium added per day, but magnesium depletion is at least 10x slower, so to see a 50 ppm drop in magnesium may take a very extended period.

Did you test your new salt water?

I added add a bit of salt the other day to compensate for new top-off added after setting up a calcium reactor (not yet running), but that was maybe two scoops over a total water volume of around 220g.