Sprulina contain protein, iron, vitamins and mineral. Also very rich sorce for vitamin A. Its only vege that contain B12 which calms your nerves and stress. Reduce cholesterol and benefits the heart.
As for Multi-vit more like a supplement, everyday or every other day. Help you store energy in your body.
Both items contain some Vit-B or A, but they kind of do different things for you.
From my personal experience Multi-vitamin got aleast 36 formula or more in 1 tablet, so means each formula it's around.2mg.1mg..so your liver wont over load, even you take spirulina and multi-vit at the sametime.