Magnesium a little too high

[GoJimmy]

Hello R2R

I thought I would throw this question out there to see if anyone is experiencing the same results. My tank has been running since the new year. Everything is stable and corals are growing and coloring well. I have switched salts back in April to Reef Crystals from Kent. Parameters are all good except mag which is always slightly high 1480-1500 without supplimentation. Other parameters are:
PH 8.2
Cal 450
Alk 8.5 steady
Nitrates 2.0
Phosphates 0.05 steady
Temp 78 steady on controller
I have been testing with Red Sea pro mag test kits. I have done a zillion tests, all with the same results.
I don't think it's detrimental for the tank as it is stable and looking great. I just am curious why my mag is so high? Either I'm testing wrong or its stable at 1480? Even after a water change. Freshly mixed salt water is around 1400. But after its mixed in the tank, it rises. Even with the Kent, same results. That's why I tried a new salt.

 

[Wilsoni]

I would test your Magnesium value against a Salifert test kit. The Red Sea Pro kit is great, the Mg test specifically, not so great...

I've read numerous articles of people getting wildly different results with that kit.

 

[Wilsoni]

I would say your true Magnesium value is probably closer to 1400 and if everything looks great I wouldn't worry about it. 1600+ is when you may want to begin taking action.

 

[GoJimmy]

I would test your Magnesium value against a Salifert test kit. The Red Sea Pro kit is great, the Mg test specifically, not so great...

I've read numerous articles of people getting wildly different results with that kit.

Thanks Wilsoni. That was my next step except I get a baseline reading of 1400 from new SW. Regardless of how many small water changes I do, it doesn't move the total tank. Kit seems to be working...

 

[jaws789832]

Try testing newly mixed salt water. Reef Crystals seem to run high on mag

 

[Downbeach]

What's your SG? The Mg in RC should be testing around 1450ppm @ 1.026(if accurate). So, given the margin of error and some noise in test kits, I'd say you're pretty close to what it should be.

 

[jaws789832]

heheh we posted at about the same time. I am in the same boat. Using RC my tank seems to stay about 1500 mag and that is using salifert test kit. I dose alk and cal but never have to dose mag because my water changes keep it up there

 

[rjl45]

I switch to RC from Kent about 8 weeks ago, and observing the same thing. Mag is always 1350-1450 running biweekly water changes. I have to dose Alk and calc to maintain levels.

Thanks for posting the question. Was going to myself when I saw this thread.

 

[GoJimmy]

heheh we posted at about the same time. I am in the same boat. Using RC my tank seems to stay about 1500 mag and that is using salifert test kit. I dose alk and cal but never have to dose mag because my water changes keep it up there

I dose kalk for cal and alk too. Good to know it is constant even with Salifert. I don't want to buy another test kit for Mag. It is stable and since I don't dose, I only test occasionally.

 

[GoJimmy]

What's your SG? The Mg in RC should be testing around 1450ppm @ 1.026(if accurate). So, given the margin of error and some noise in test kits, I'd say you're pretty close to what it should be.

I do mix to 1.26SG. I just tend to get nervous when it creeps up over 1500ppm. If I mix to less than 1.026, my cal and alk are too low. I suppliment with kalkwasser and at 1.026, it holds cal and alk perfectly.