Hey hey wwr you're doing a good job don't let the rust worry you, happens to the best of us.
Plants love their cal-mag in flower so you need to give it to em before they start rusting :/
Well now you know, so you're set.
Otherwise, some killer plants bro.
Are you making some seeds or what ?
That AA2 looks dark green and quite healthy.
Anything different with its food/soil mix ?