Magnesium consumption

Dw79 · Jul 19, 2020

My magnesium has been going down a lot lately. I just did a 4 day test and it went from 1400 down to 1360, so 10ppm a day. That seems like a lot to me. There is a lot of coralline growth going on, so would that account for the drop, or is this a normal amount of consumption?

Randy Holmes-Farley · Jul 19, 2020

Dw79 said:
My magnesium has been going down a lot lately. I just did a 4 day test and it went from 1400 down to 1360, so 10ppm a day. That seems like a lot to me. There is a lot of coralline growth going on, so would that account for the drop, or is this a normal amount of consumption?

Can only be test error or a salinity drop.

You'd need to consume about 400 ppm calcium and 56 dKH of alkalinity to actually consume 40 ppm of magnesium.

Dw79 · Jul 19, 2020

Randy Holmes-Farley said:
Can only be test error or a salinity drop.

You'd need to consume about 400 ppm calcium and 56 dKH of alkalinity to actually consume 40 ppm of magnesium.

Lovely. I can't win with test kits. Just got this one, because the last one I had read 1200 no mater what you did to it. What is a normal daily rate an average tank uses?

Randy Holmes-Farley · Jul 19, 2020

Dw79 said:
Lovely. I can't win with test kits. Just got this one, because the last one I had read 1200 no mater what you did to it. What is a normal daily rate an average tank uses?

Normal is 1/10th of the calcium consumption, so 0-2 ppm per day.