Sudden drop in Magnesium??? Caused by skimmer???

bimmer88

New member
My mag normally drops about 10ppm a week since i've been testing about 5 months ago... i test every other week... haven't been adding any mag recently because I was actually trying to drop it lower.. initially had it at 1430 and i've been wanting to get it down to about 1350.. 2 weeks ago I had it at about 1380... when i tested today, it had dropped down to 1275 based on the salifert test kit. I didn't believe the first time i tested so i tested again and same thing... i have not added any new corals... the only thing that changed was that last week i changed out my older skimmer for a skimz skimmer... the new one is skimming like a beast but could it be possible that it's skimming out my magnesium???
 

zigzag1

New member
IME, the skimmer isn't the reason for your Mag drop. Consumption perhaps. Coraline growth maybe. Keep looking.. JMTC & GL!
 

bertoni

Premium Member
I agree that the skimmer shouldn't be the issue. My biggest source of magnesium drops was water changes, because I forgot to dose up my Instant Ocean. That rate of consumption seems fairly reasonable, until the last big drop. I'm not sure what happened there if you didn't do a water change.
 

tmz

ReefKeeping Mag staff
Premium Member
Perhaps, the removal of organics and increased aeration via the new skimmer created water conditions more conducive to growth by calcareous organisms thus increasing consumption of magnesium, carbonate and calcium. Did other parameters change: ph, calcium alk,for example? A waterchange is moe likely since the last drop is higher than would be reasonably expected. Has salinity been constant? A drop there would also affect the overall mag level.
 

bimmer88

New member
I don't do any large water changes... just about 10 gallons a week in my 180... nothing else changed besides magnesium... i dose b-ionic 2 part daily... here are my parameters:

-nitrates: 0ppm
-alkalinity: 8.5dkh
-calcium: 420ppm
-phosphates: .02ppm
-salinity: 1.026
 

bertoni

Premium Member
I'm not sure what happened. I guess I'd dose the level back up and see whether there's any issues going forward.
 

Psyops

Still Learning
do you have another mag test kit? Or a friend with one? I have noticed my mag kits in the past suddenly dropped in measured value. This is the Salifert brand I am referring to. I have not used others. My problem was that I was not capping the reagants fast enough. Hope this helps.

Or maybe use your premixed saltwater as a reference before doing the next water change. See what you get there. That's how I figured it was my kit, since I got 200 ppm lower on the premix salt also from past values.
 
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