Magnesium Level constantly dropping! Help Please.

makers marc

New member
Hey everyone,

. In a nutshell, my Mg. level constantly reverts to 1200 ppm from 1300-1350 only 1 week after supplementing with the DIY recipe of Randy Holmes Farley - which calls for a mixture of magnesium cholride and magnesium sulfate using Epsom Salts and BRS Magnesium Chloride.

Based on the infamous online calculator, with a net water volume of 65 gallons Im supposed to add 26.5 floz slowly over several hours and never enough to increase by 100pm per day. I test 24 hours later and my Red Sea Pro test kit shows 1350.

Either way, in a week it always falls back to 1200.

1. Is this normal? Ive always read that it takes a lot to bring up Mg. but once its up there it maintains fairly constant with water changes.

2. I surmised that it could be low Mg. levels from using Aquavitro Salinity which seems to always be lower in Mg. and Ca. than the stated ranges. So I skipped my 15% weekly WC and the levels still dropped to 1200.

3. Is it possible my corals are consuming this much? I only have mini colonies or frags so I doubt it, but stocking list is:

Frogspawn (6 heads)
Elegance Coral
blastos (20 heads)
Trumpet Coral (10 heads)
bubble coral
purple xenia
2x zoa rocks about the size of a tennis ball
Toadstool Mushroom size of softball
Devils Hand leather
digitata
maxima clam
 

spieszak

New member
What salt do you use? Are you check at/around water changes?
I can't remember the last time I actually had to dose Mg, but I have a friend who dosed it regularly for like a year...
 

outssider

New member
my tank uses mag. at the rate 1/6 the amount of calcium. I dose everyday, if I didn't, mine would probably drop just like yours is...
 

Sounds Fishy

New member
I noticed my Mg. seems to get low too,and I always seem to think it's related to the reef crystals I use during water changes.
 

Sounds Fishy

New member
The container for Aqua Vitro gives a guaranteed analysis for Mg as being 1269,up to just over 1400.So if your water changes are around the low end of the spectrum (1269) and your aquarium is using up Magnesium,anyway,I could see why it drops.
 

downbeach

New member
I ran a mixed reef for many years, and never had to dose Mg. My WC's were enough to keep up with any demand from my system. The uptake of Mg is typically around 1 - 2 ppm per day, so using 150 ppm in a week would be unlikely. Have you tried another test kit?
 

makers marc

New member
I ran a mixed reef for many years, and never had to dose Mg. My WC's were enough to keep up with any demand from my system. The uptake of Mg is typically around 1 - 2 ppm per day, so using 150 ppm in a week would be unlikely. Have you tried another test kit?

No, I guess I could but this has been consistent for 6 months now. So I cant imagine how that test could reflect a similar pattern over that course of time.

But I didnt know thats the rate in PPM thag Mg normally drops. Is it possible to skim it out?
 

power boat jim

Well-known member
No, I guess I could but this has been consistent for 6 months now. So I cant imagine how that test could reflect a similar pattern over that course of time.

But I didnt know thats the rate in PPM thag Mg normally drops. Is it possible to skim it out?

No it doesnt skim out. Mag levels should be roughly 3x the calcium level. So, not knowing what the calcium level is in the tank its a nearly useless number. 1200 would seem fine since that would indicate a level of 400ppm for ca. The balance between those two is more important then the Mg number alone.
 

makers marc

New member
No it doesnt skim out. Mag levels should be roughly 3x the calcium level. So, not knowing what the calcium level is in the tank its a nearly useless number. 1200 would seem fine since that would indicate a level of 400ppm for ca. The balance between those two is more important then the Mg number alone.

My calcium level rises to roughly 400-425ppm after dosing Kent Turbo Marine weekly, then stabilizes at 375ppm.

So that 3:1 ratio applies here I guess... So now that Im trying to transition to SPS mainly, how would I raise my Ca to 450-500ppm? I've always dosed my Mg first to try and get it above 1300ppm before raising Ca, since I've read that you want Mg higher so that Ca and Alk stay balanced.

But if I cant get my Mg to get above 1200, can I still dose Ca without fear that Alk will drop?
 

power boat jim

Well-known member
My calcium level rises to roughly 400-425ppm after dosing Kent Turbo Marine weekly, then stabilizes at 375ppm.

So that 3:1 ratio applies here I guess... So now that Im trying to transition to SPS mainly, how would I raise my Ca to 450-500ppm? I've always dosed my Mg first to try and get it above 1300ppm before raising Ca, since I've read that you want Mg higher so that Ca and Alk stay balanced.

But if I cant get my Mg to get above 1200, can I still dose Ca without fear that Alk will drop?

Just maintain the numbers you have for the sps. driving up Ca numbers wont make anything grow faster. Coral only grows at a certain rate no matter what the Ca level is. If you have a stable tank at slightly lower then 425 ppm Ca and about 1200 ppm Mg you are fine.
 

makers marc

New member
Just maintain the numbers you have for the sps. driving up Ca numbers wont make anything grow faster. Coral only grows at a certain rate no matter what the Ca level is. If you have a stable tank at slightly lower then 425 ppm Ca and about 1200 ppm Mg you are fine.

Im sure youre right. But still doesnt let my OCD stop being curious as to why this is happening? Test kits? Color blind lol? Hydrometer sucks? Precipitation?
 
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