What would cause Magnesium to rise?

[d2mini]

My 25g Nuvo Fusion Lagoon has been anything but stable.
I'm dosing Randy's Two-Part Alk recipe #2 and BRS Calcium.
I've tried running them both on the same timer and that failed.
Alk was good but Calcium shot well into the 600's.
But that's fine, that's fixable.
What I can't seem to fix (other than with massive water changes) is a continuous rise in Magnesium.
It was over 1800 at one point. I brought it down with the massive water changes to 1300 or so, and now it's back to 1500ppm.
What could be causing this?!
My LPS are fine but my SPS are obviously not happy, I've lost a lot. And some have been STN'ing underneath, in the shadow areas. (my lighting is a 150w MH and two blue reefbrite strips).
Any insight would be appreciated.

Other info... i have Marine Pure spheres in the filter compartment. I did try some carbon in there too but have pulled that out. Had also had Chemi-pure Blue at one point (another carbon). No phosphate media. And I run the Ghost skimmer.

 

[CodyRVA]

Just curious, but what's your salinity and what salt are you using?

 

[d2mini]

Just curious, but what's your salinity and what salt are you using?

1.025 and AquaVitro Salinity which I've always used on my tanks.

 

[tj w]

Wow, I have to dose mag into my tank once a week just to keep levels up. I'll be following to take notes...beautiful build by the way

 

[Randy Holmes-Farley Verified Community Expert]

Nothing causes magnesium to rise except rising salinity, or adding it somehow.

It might be testing error.

Are you using the Red Sea kit? Many folks have issues with it.

 

[d2mini]

Nothing causes magnesium to rise except rising salinity, or adding it somehow.

It might be testing error.

Are you using the Red Sea kit? Many folks have issues with it.

I'm using the NYOS kit and I thought about test error but it does seem to rise and fall with water changes.
Like how I said above that it was sky high but I got it to come down to normal levels with several massive water changes.
And now since I backed off on the water changes it has gone up a bit again.
I do have an unopened Red Sea Reef Foundation Pro Test Kit sitting here that I could try.

 

[Ontheway]

How much Mg do you read in fresh-prepared water for change? If you read normal values, this eliminates test errors.
Since the situation seems critical, I would remove everything used for filtering purposes. May be something stuck in there.
How do you supply ca and alk? Dosing pump or Reactor? Might be good idea to test their outputs for Mg, also.

 

[d2mini]

How much Mg do you read in fresh-prepared water for change? If you read normal values, this eliminates test errors.
Since the situation seems critical, I would remove everything used for filtering purposes. May be something stuck in there.
How do you supply ca and alk? Dosing pump or Reactor? Might be good idea to test their outputs for Mg, also.

Just tested the fresh saltwater and it read a bit high at 1440.
I tested the tank water with the Red Sea Pro kit and it tested same as the NYOS, about 1520.
So i think the test kits are ok.

The two-part is dosed via BRS dosers.

 

[Ontheway]

Although mg tests are longest to do ones, I may highly advise to check mg content of dosing Containers too. In the past, I mixed up container numbers and kh pumped alot, instead of Ca.

 

[Randy Holmes-Farley Verified Community Expert]

For magnesium to rise by 300 ppm in a 100 gallon tank would take huge amounts. It is not a trace chemical leaching from something. If you want to do that with pure anhydrous magneisum chloride (about the most potent chemical around for magnesium addition), it will take about a pound of solid to dissolve.

 

[d2mini]

For magnesium to rise by 300 ppm in a 100 gallon tank would take huge amounts. It is not a trace chemical leaching from something. If you want to do that with pure anhydrous magneisum chloride (about the most potent chemical around for magnesium addition), it will take about a pound of solid to dissolve.

Ignore my sig, this is for a 25g gallon tank. I mentioned that in my OP.
But I get your point. I'm stumped!

 

[Sabellafella]

I'm using the NYOS kit and I thought about test error but it does seem to rise and fall with water changes.
Like how I said above that it was sky high but I got it to come down to normal levels with several massive water changes.
And now since I backed off on the water changes it has gone up a bit again.
I do have an unopened Red Sea Reef Foundation Pro Test Kit sitting here that I could try.

I use the nyos too, acually think its the best hobby mag test kit out. Are you using 2 part?

 

[d2mini]

I use the nyos too, acually think its the best hobby mag test kit out. Are you using 2 part?

randy's alk recipe and brs 2-part.
and yeah, the nyos is super easy for a mag kit.

 

[Randy Holmes-Farley Verified Community Expert]

Are you using tap water for top off?

Any chance you confused a mag additive for calcium?

 

[d2mini]

Are you using tap water for top off?

Any chance you confused a mag additive for calcium?

lol, nope. RO/DI with zero tds.

And no on the mag/calc confusion. I don't even have magnesium supplement. 6 months ago i purposely raised it with some epsom salt to fight some algae but that was it.
Think there could be residual salt in the sand bed or something?

 

[Randy Holmes-Farley Verified Community Expert]

6 months ago i purposely raised it with some epsom salt to fight some algae but that was it.
Think there could be residual salt in the sand bed or something?

No, it dissolves instantly.

 

[Ontheway]

Alk was good but Calcium shot well into the 600's.

Randy, I know from your article that Mg removes Ca from surfaces and mounts itself (the 'figure 9'), to a certain surface depth. Is reverse possible with excessive Ca (In case if Ca was dosed more then needed, accidentally) ?
Or;
Wonder if high Mg was the cause of increase in Ca, reported above.

 

[Randy Holmes-Farley Verified Community Expert]

Randy, I know from your article that Mg removes Ca from surfaces and mounts itself (the 'figure 9'), to a certain surface depth. Is reverse possible with excessive Ca (In case if Ca was dosed more then needed, accidentally) ?
Or;
Wonder if high Mg was the cause of increase in Ca, reported above.

No, these surface effects are so thin that you'd have to look very hard to find the very small change in the bulk water concentration in either direction.