How much Magnesium to dose?

[rishu_pepper]

Will add 750mL tonight (half of the recommended dosage) and check back with a Mg test tomorrow morning. My levels are all pretty low since I haven't dosed at all since the tank began 3 months ago, all I've done are simple 25% monthly WCs. Still working on getting N and P down, Foz-down since last month and vinegar dosing recently.