Magnesium vs Calcium

Schteeve · Nov 26, 2019

Hey all,
is there a way to decrease Magnesium levels and increase Calcium levels (apart from the obvious water changes)
My Magnesium is way too high and its affecting my waters ability to uptake Calcium

Spare time · Nov 26, 2019

How high is the magnesium? I wouldnt imagine it having any effect on your calcium levels but I am not a chemist so I'm not 100% sure. I would just do water changes or let it fall naturally (if it's not too high).

Randy Holmes-Farley · Nov 26, 2019

No, there is no good way to remove magnesium from reef tank water.

Randy Holmes-Farley · Nov 26, 2019

What makes you think the magnesium is causing calcium uptake issues? I think that is very unlikely in a reef tank.

Schteeve · Nov 26, 2019

I dont have many Corals in my tank so far, and magnesium isnt really being consumed all that fast.
My Mg is currently sitting at 1600+
in my thinking this would inhibit calcium dissolving into the solution as its already got a lot of Mg salts in it

Randy Holmes-Farley · Nov 27, 2019

Schteeve said:
I dont have many Corals in my tank so far, and magnesium isnt really being consumed all that fast.
My Mg is currently sitting at 1600+
in my thinking this would inhibit calcium dissolving into the solution as its already got a lot of Mg salts in it

that does not happen.

Vansaquaescape · Nov 29, 2019

I got a question because I made a post and nobody really answered to it. My magnesium right now is at 1300 last night it was at 1400 ppm. I dosed Kents magnesium got it up to 1390 within a week it was back down to 1300 my magnesium never really drops past 1290 ever but I can’t keep it up at 1400. What can be causing the magnesium to just vanish. Calcium is 440 alkalinity 9.3 and yet I can’t keep my magnesium at 1400

Randy Holmes-Farley · Nov 29, 2019

Magnesium cannot ever jump up or down more than a few pm in a day unless you dose enough to do so, or salinity is changing a lot. Test error is the very common explanation for such variations.

Vansaquaescape · Nov 29, 2019

Randy Holmes-Farley said:
Magnesium cannot ever jump up or down more than a few pm in a day unless you dose enough to do so, or salinity is changing a lot. Test error is the very common explanation for such variations.

Then it Has to be my test kit but I’m using the salifert for magnesium test kit went to my LFS and they got an even lower reading than I did. That’s what I don’t understand is that my salinity isn’t fluctuating DKH and calcium isn’t fluctuating but literally this stuff is dropping 100 ppm in a day. I have a new test kit on order and should be here in the next few days to see if it was the kit or what the deal is

Randy Holmes-Farley · Nov 30, 2019

Many users results with test kits are less repeatable than they assume. Magnesium seems especially problematic for many people.

Rest assured that it is 100 percent certain that magnesium is not fluctuating 100 ppm in a day.