When you activate Secret of arcana it last for 1 minute in most cases. I have discovered that on the PS4 edition ( and possibly others) that if you cast a spell that can be held instead of single cast during the 1 minute of no spell cost, the spell will never require magicka as long as you never recast the spell. In combination with the telekinesis spell, this can be used to level alteration very fast if the player holds an item and fast travels to places, and level the player very fast. So fast that it makes speed running athe ebony warrior a viable thing in combination with other bugs. And so I have done that and killed the ebony warrior in 2 hours 44 minutes.