Mag Dropping Recently

[Aaron Soliz]

Hi everyone,

having an issues with my mag dropping in the past two weeks. Usually it’s around 1400 because that is where my saltwater when mixed comes up as. I have a 10 gallon nuvo fusion that’s been doing well but I noticed some recession on my hammer coral (tissue wise) and I’m trying to fix the issue.

Alk is 9.0 where it always is
Calcium is always at 440-450
pH is at 8.2
Nitrate is between 25-30ppm
Phosphate: usually is at .01 but i have been doing my best to keep it at .03-.04

i have been dosing Neophos once a week. Only 2 to 3 drops after i do my weekly one gallon water change. I feel since I have been adding the Neophos… that my mag is declining. Last week it was at 1365 and today it’s not at 1290. I just mixed up some fresh saltwater and tested it and my mag came out to 1410 so i know it’s not my test kit.

could dosing neophos once a week be the issue with my Mag all of a sudden dropping the way it is?

 

[blaxsun]

Do you have a lot of coralline algae growth? That can consume a fair bit of magnesium.

 

[Aaron Soliz]

Do you have a lot of coralline algae growth? That can consume a fair bit of magnesium.

I actually not. Very little. I wonder if I’m going to have to start dosing it.

 

[blaxsun]

I actually not. Very little. I wonder if I’m going to have to start dosing it.

You may be on the verge of a bumper crop of coralline. My magnesium was just getting sucked up left, right and center for the longest time. Everything is purple...

 

[Aaron Soliz]

You may be on the verge of a bumper crop of coralline. My magnesium was just getting sucked up left, right and center for the longest time. Everything is purple...

What did you do in order to keep it where you wanted it at? Do you dose mag now?

 

[blaxsun]

What did you do in order to keep it where you wanted it at? Do you dose mag now?

I just kept dosing magnesium until the daily requirement dropped off. Yea, but it's probably a third now of what it was previously.

 

[thatmanMIKEson]

Easier to rang magnesium with multiple tests, because of the accuracy of magnesium tests, if using salifert draw the syringe to 1ml the reagent @ 8 ml's for every test the value may not be exact but from test to test preformed the same every time, try to notice a trend. Then when the trend is noticed pick a range in the middle as to not be to high or low.

 

[Randy Holmes-Farley]

Bear in mind that real magnesium consumption is not more than about 1/10th of the calcium consumption and is rarely more than 1-2 ppm per day.

Anything much above that is test error or salinity changes.

 

[Aaron Soliz]

Easier to rang magnesium with multiple tests, because of the accuracy of magnesium tests, if using salifert draw the syringe to 1ml the reagent @ 8 ml's for every test the value may not be exact but from test to test preformed the same every time, try to notice a trend. Then when the trend is noticed pick a range in the middle as to not be to high or low.

That’s correct. I do use salifert. I pull the syringe to 1 and the reagent is at 8.5 every single time. I know some salifert test need for it to stop at 8.5 while some don’t.

 

[Aaron Soliz]

Bear in mind that real magnesium consumption is not more than about 1/10th of the calcium consumption and is rarely more than 1-2 ppm per day.

Anything much above that is test error or salinity changes.

Hmmm interesting. I’m going to test my salinity today. I never have had to but I’ll see. I feel pretty spot on with it because my water changes… i test the water before adding it into my tank. It’s a pain but well worth it. I’ll try the mag test again on my display tank. Hopefully it was just an issue then. We shall see.

 

[RBarth]

Bear in mind that real magnesium consumption is not more than about 1/10th of the calcium consumption and is rarely more than 1-2 ppm per day.

Anything much above that is test error or salinity changes.

Interesting. I have a 40g tank that requires 1ml of calcium a day but 10ml of mag.

 

[Randy Holmes-Farley]

Interesting. I have a 40g tank that requires 1ml of calcium a day but 10ml of mag.

Assuming you mean my diy recipes, that’s not offsetting consumption. Might be offsetting water changes with new salt water that doesn’t match your target.

 

[RBarth]

Lol...think u just confused me there. I keep my mag around 1500. Never tested my newly made RS BB salt for mag but when I first set up my doser I tested everything daily for a month. I do 25% water changes every week and 10mls is what keeps it at 1500.

Ps. Sorry for the sidetrack!!!!

 

[thatmanMIKEson]

That’s correct. I do use salifert. I pull the syringe to 1 and the reagent is at 8.5 every single time. I know some salifert test need for it to stop at 8.5 while some don’t.

Yeah I've seen 8.5 but not always easy, I find that it likes to get to 8ml pretty easily.

I find it easier to do my test the same every time weather at 8 or 8.5 then notice the trend, its a large range for mag and not so necessary to be spot on and our testing will never be "spot" on anyway

 

[thatmanMIKEson]

I just pre ordered the Hanna mag test I hope its awesome and helps with mag testing in the future!

 

[Randy Holmes-Farley]

Lol...think u just confused me there. I keep my mag around 1500. Never tested my newly made RS BB salt for mag but when I first set up my doser I tested everything daily for a month. I do 25% water changes every week and 10mls is what keeps it at 1500.

Ps. Sorry for the sidetrack!!!!

1500 ppm magnesium is pretty high and is much higher than Red Sea claims for their blue bucket salt mix at 35 ppt (sg = 1.0264) which is 1290 ppm.

Thus, those additions of yours are offsetting the salt mix water changes.

 

[Aaron Soliz]

1500 ppm magnesium is pretty high and is much higher than Red Sea claims for their blue bucket salt mix at 35 ppt (sg = 1.0264) which is 1290 ppm.

Thus, those additions of yours are offsetting the salt mix water changes.

My blue bucket gives me a 1410 every time. I wish it was a bit more consistent to what it shares that it is supposed to be at which is 1290 as you shared. Calcium is always spot on though.

 

[Randy Holmes-Farley]

My blue bucket gives me a 1410 every time. I wish it was a bit more consistent to what it shares that it is supposed to be at which is 1290 as you shared. Calcium is always spot on though.

Might be Red Sea does not make what they claim, or your mag test is off, or the salinity is higher than 35 ppt.

All are quite possible.

Here's where they make the mag claim (click the picture to read it better):

Another Test Post EN

This Tips & Tricks blog will provide you with great practical advice on how to ensure a consistent and perfect mix every time. Advice on how to ensure a consistent and perfect mix every time.

www.redseafish.com

 

[Aaron Soliz]

So i just did a water change. As i mentioned yesterday, my mag is at 1410 with my new water that I’m adding into the tank which is 1 gallon. I just checked my mag 4 hours after doing the water change… it’s sharing I’m at 1275. Yesterday it’s was at 1290.

this is kinda driving me bonkers on why it’s doing this. Salinity is at 1.024. Little low but i don’t think enough to throw it off like this.

 

[Randy Holmes-Farley]

Sure it can. Take 35 ppt seawater (sg = 1.0264) with magnesium at 1300 ppm and drop the sg to 1.024 and magnesium drops to 1182 ppm.