Dosing magnesium

[asylumdown]

Ok ok, I know I'm supposed to know this and shame on me for not spending 45 minutes on google figuring this out, but how exactly am I supposed to dose magnesium again? It's been a long time since I've had to worry about this, but after a year of my tank just managing fine on water changes alone, my mag levels are trending downward and I think I need to start dosing.

There seems to be so many ways to do it, epsom salts, epsom salts plus some other magnesium chemical, dosing with a doser, dosing mixed in with the calcium solution, dosing by hand once every so often, etc. etc. etc.

What does everyone here do to maintain magnesium levels and why?