Low Magnesium levels - is it bad?

[westwind77]

My Magnesium level was low when I tested last week, around 800-900. What can low Magnesium cause?
I bought some Kent Tech M Magnesium and have been dosing about 100ml per day for the past few days and it is creaping but up, around 1100 or so. I am wanting to bring it back up to 'normal' I read on Kent's site that they say it plays an important role in maintaining Calcium levels, but I have never had an issue with calcium, always around 450.
I noticed the drop in Mg after I started to run carbon in an in-line filter system I have, does that sound like it could be causing the drop?
System is a 110g, I use Oceanic salt and do a 10g water change every week.

 

[jackri]

If you don't keep coral it shouldn't be an issue... otherwise your calcium/alk/pH and mag all play an interchanged role together.
Mag should ideally/roughly be 3 times your calcium.

 

[my time]

If your magnesium is low it will become hard to increase calcium levels and maintain them no matter how much calcium you add.Sometimes it will look like snow when adding calcium to your tank if your mag. is low.Natural sea water has 1.320mg/l.Cheap salt mixes also have very low magnesium so be aware.Good luck

 

[gc1962]

I also use oceanic salt and my magnesium levels were around what you stated so the next batch of salt I mixed up I tested and the levels were around 900 also. I believe the oceanic salt mix is low in magnesium but I like the calcium levels of it.

 

[funkpolice]

I'm in the exact same situation as you westwind, I'm interested to hear an answer.
bill

 

[natclanwy]

I think oceanic is low in mag as well, I am using it too and have trouble maintaining my mag because I drip kalk which causes magnesium to precipitate out and water changes don't have enough magnesium to replace what is being precipitating out.
Carbon won't remove significant quantities of magnesium, the largest consumer of magnesium is coraline algae.