View Full Version : What could deplete Magnesium?

07/01/2010, 08:15 AM
Hi, I have been dosing Randy Mag receipe 60ml everyday for a week, but the level never go up a single bit. Is there something in the tank that use up the Mag that much? tank is 150g total volume, Mag 1250, Ca 370, Alk 2.6, pH 7.9, Sal 1.025...


07/01/2010, 10:02 AM
Your alk is crazy low! If that is a correct reading you need to increase this to at least 7dkH. You may want to look at using someone else's test kits for reference as most kits do go bad.

07/01/2010, 10:14 AM
Is your alk in meq/l? If so it's on the low side of the acceptable range 7 to 11 dkh but it's ok ( 2.6 meq/l = 7.3dkh). Corals coraline and other calcareous organisms use magnesium. How much magnesium does your salt mix have?

07/01/2010, 10:29 AM
The amount your are dosing only increases your Mg by about 5ppm which isn't much. You might need to up your dosing a fair bit?

07/01/2010, 02:57 PM
I believe Kent's mag states using 1ml per gallon of water daily until desired level is reached, then dosing only to keep the level consistant. (Kent's is what I use) only reason I mentioned it...

07/01/2010, 03:29 PM
Assuming there's 150 g of water in the tank, it should take about 600 ml to increase magnesium by about 50 ppm, which is small enough that a hobbyist test kit might have an issue resolving it.

I'm assuming the alkalinity is 2.6 meq/L.

Some organisms will consume magnesium:


Most any organism that deposits calcium carbonate will consume some magnesium in the process, although the percentage varies.

07/01/2010, 09:16 PM
I use IO, and 2.6 meq/L is correct. I just want to play safe so I just dose little bit every day. But even so, my Mag level should be up little, correct? Also, Can I dose the Baking soda the same time to bring up the Alk to the 3 level?

07/02/2010, 04:37 PM
The magnesium should be up a little bit, but our test kits don't necessarily resolve that well. I'd just keep on dosing for a couple more weeks, and check the level maybe once a week. Some people do report a fair amount of magnesium consumption.

Baking soda is fine to dose along with the magnesium, and alkalinity at 3 meq/L is fine. :)

07/02/2010, 09:32 PM
Thanks Bertoni.

07/02/2010, 09:33 PM
You're welcome! Good luck!