Magnesium

fachatga

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If your salinity is very low because your not using enough salt mixture due to testing error then it can be the problem since most salt mixes have plenty of magnesium and there where your tank will get most if not all of it from. So good to make sure you’re measuring it correctly.
 
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If your salinity is very low because your not using enough salt mixture due to testing error then it can be the problem since most salt mixes have plenty of magnesium and there where your tank will get most if not all of it from. So good to make sure you’re measuring it correctly.
Yup. I just did a calibration with RODI and realised that’s the reason. I’m annoyed. About to do a water change
 

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Yup. I just did a calibration with RODI and realised that’s the reason. I’m annoyed. About to do a water change
Rodi shouldn’t be used to calibrate. You should use a solution around where you want the tank (1.0265 is a common calibration standard) instead of doing a water change just top off with salt water. I would only water change if you are really really low but right now you don’t actually know how off you are.
 
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Rodi shouldn’t be used to calibrate. You should use a solution around where you want the tank (1.0265 is a common calibration standard) instead of doing a water change just top off with salt water. I would only water change if you are really really low but right now you don’t actually know how off you are.
Alrighty I’ll do that, but I did water change because my salinity was pretty low
 

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What was your salinity before a water change? Hopefully it wasn't a big increase.. always adjust things over a period of time. Even if its over a few days. Sudden increases could have a mass inpact on the tank life
 
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What was your salinity before a water change? Hopefully it wasn't a big increase.. always adjust things over a period of time. Even if its over a few days. Sudden increases could have a mass inpact on the tank life
I think it was something like 1.020 but everything looks fine right now
 
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What was your salinity before a water change? Hopefully it wasn't a big increase.. always adjust things over a period of time. Even if its over a few days. Sudden increases could have a mass inpact on the tank should I still dose
Rodi shouldn’t be used to calibrate. You should use a solution around where you want the tank (1.0265 is a common calibration standard) instead of doing a water change just top off with salt water. I would only water change if you are really really low but right now you don’t actually know how off you are.
What was your salinity before a water change? Hopefully it wasn't a big increase.. always adjust things over a period of time. Even if its over a few days. Sudden increases could have a mass inpact on the tank life
Should I still dose magnesium?
 

ReefRusty

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I think it was something like 1.020 but everything looks fine right now
What has your salinity been increased to now? Hopefully it fixes your magnesium issue, you will probably see an increase in cal and alkalinity as well die to using more Salt..

Magnesium would be the least consumed of the 3 but alkalinity and calcium work with and against each other. Depending of what corals you have, generally at the start every water change is enough to keep levels at a good point.

But when you start adding life and corals they will start to be consumed and will need to dose every day to keep it at a good level without large swings in your parameters.
 

Randy Holmes-Farley

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Would this help magnesium?

Yes. Every element in seawater is raised or lowered as you raise or lower the salinity.

If your salinity is very low, that could explain very low magnesium.
 

Randy Holmes-Farley

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I think it was something like 1.020 but everything looks fine right now

That very low specific gravity is the problem.

If you boost it to natural seawater levels (sg = 1.0264), magnesium will rise to actually higher than normal seawater levels.
 

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