Good advice from JK.

Vitamin C is very important during mercury toxicity because mercury blocks it and people end up with easy bruising, spider veins, and other C-deficient diseases.

I take malic acid with C because C causes aluminum retention but malic acid will chelate the aluminum, and it seems to work very well for me.

This is what I currently take for malic acid:
Fibralgia

About magnesium... I am currently mercury toxic from heavy chemtrail spraying in our area and when I take 1200mg of this:

Magnesium Complex

Things work perfectly. In fact, 1200mg is the "sweet spot" for me right now.

Most mercury toxic people need a lot of magnesium...An amount that would cause a normal non-toxic person to get diarrhea. Of course, without mercury toxicity, I didn't need any magnesium at all.

Why you can take all that C and not have side-effects? I would explore an absorption issue or what type of C is being used. I currently use this:

Citrus Bioflavonoids for my C and if I take too much, I can definitely feel it.

Hope this helps.