Help reading results on my Salifert magnesium test

[Mary Carmen]

Hi all!
I am testing magnesium using the Salifert test kit and I always have to add .1 of the Mg-3 to make the tube water change from pinkish purple to blue. I need help computing the magnesium concentration in my tank since the chart is based on using only 1 ml. Anyone can help me with the value and explain how it is done?
Thank you for your time!!
Mary

 

[1WildBill]

I was using the Salifert mag test and it was telling me I had no mag. I jumped to Red Sea test kits and there was mag all along. Salifert has a Utube channel that will show you how to do the test.

 

[lapin]

Hi all!
I am testing magnesium using the Salifert test kit and I always have to add .1 of the Mg-3 to make the tube water change from pinkish purple to blue. I need help computing the magnesium concentration in my tank since the chart is based on using only 1 ml. Anyone can help me with the value and explain how it is done?
Thank you for your time!!
Mary

Watch this then if you have a question ask me

 

[Mary Carmen]

I actually watched that already. I used the same method. My problem is that the water sample on the test tube doesn't turn blue after I add all 1ml of Mg-3. After I use up all the Mg-3 solution, my water only turns purple. I then add .2 more of the Mg-3 solution to my syringe and it turns blue after I use up only .1 ml. I know that my tank has more than 1500 mg/L magnesium.
The way I have been calculating the results is as follows, but it throws me off that we calculate the level of Magnesium by counting the leftover liquid in the syringe.
I know the table has an increase of 150mg/L per .1 ml of Mg-3 liquid that you add to the test tube. So, do I add 150mg/L to my reading? Sounds too simple.
Thank you!

 

[lapin]

I know the table has an increase of 150mg/L per .1 ml of Mg-3 liquid

1500 for the 1ml
150 for .1ml
1650 is your reading
That is pretty high.

 

[Mary Carmen]

Mistery solved!
Two weeks ago, I went to my favorite saltwater shop with a sample of water from my tank. It turns out my salinity was high... very, very high.
I have been measuring salinity with the wrong refractometer.
Last week, I started 1 gallon wc per day until my salinity got to 1025.
Everything looks happier now.

 

[ShelaghM]

I actually watched that already. I used the same method. My problem is that the water sample on the test tube doesn't turn blue after I add all 1ml of Mg-3. After I use up all the Mg-3 solution, my water only turns purple. I then add .2 more of the Mg-3 solution to my syringe and it turns blue after I use up only .1 ml. I know that my tank has more than 1500 mg/L magnesium.
The way I have been calculating the results is as follows, but it throws me off that we calculate the level of Magnesium by counting the leftover liquid in the syringe.
I know the table has an increase of 150mg/L per .1 ml of Mg-3 liquid that you add to the test tube. So, do I add 150mg/L to my reading? Sounds too simple.
Thank you!

Thanks that helps me as well. But why is my magnesium not dropping?

 

[Mary Carmen]

Thanks that helps me as well. But why is my magnesium not dropping?

Do you have an automatic doser or do you dose manually?
It would be helpful to post more information about your system. In my case, I made my own salt water by mixing Rodi water and reef salt( can’t remember the name because I do it differently now). When I overdosed the salt I also raised my magnesium.

 

[hllb]

Glad you figured it out. For others, if your mg is high and you aren’t dosing, check your fresh mixed water. I had some reef crystals salt that tested at 2400 mg when freshly mixed! I switched salt and it’s slowly coming down.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks that helps me as well. But why is my magnesium not dropping?

real magnesium decline is 1/10th of the calcium decline. Too small to notice unless you monitor long term

 

[ShelaghM]

Do you have an automatic doser or do you dose manually?
It would be helpful to post more information about your system. In my case, I made my own salt water by mixing Rodi water and reef salt( can’t remember the name because I do it differently now). When I overdosed the salt I also raised my magnesium.

No I get my water from my lfs. The tank was low when I started it so I was dosing 2.5ml a day until it got to 1150 then I stopped but it kept rising to 1900. Then it began to full again until now it’s 1650. I do a 10-20% water change each week. The tank is the Red Sea reefer 250. As the calcium was low I was dosing that and KH until the calcium got to 430. The Kh is now 7.5. So I’m only dosing that now.
this rank has been running since 31/10/2019, had to transfer all corals and fish to the new tank with new water as the old tank cracked and was nearly empty when we came home. So it’s still not completely recycled but we could not do anything else. The good news was we never lost anything including our anemones.