After one day you don't see flowering. If you ALREADY had female pre-flowers, that's one thing- but full flowering response takes from 4-7 days.

MG is not so great. It has too much nitrogen, even in the 'bloom'. It's meant primarily for garden bedding plants.

You are talking about foliar bloom supplements; yes thery are out there but I suggest sticking with a base bloom fert on your first grow.