Quick Guide to hexes and Power-ups, only the strong ones where things can get confusing:
Tears of the Phoenix: Only protects from hexes and hurt points for 1 day, 24 hours from the time of the post it is used in. After that it becomes a passive power-up keeping the pony it is used on, alive.
Cadence's Love Spell: a passive power-up that protects from ALL hexes.
Discord's Trickery: Very powerful because it can take a power-up and put it on another pony. Can not be used against Cadence's love spell because it protects from hexes. Can be used on Tears of the Phoenix AFTER the protection from hexes and hurt points is gone. Can only give a pony the power-up IF it is in the same division as the pony it was originally used on. This Hex replaces the power-up, so instead of 1 power-up 1 hex, it becomes 2 hexes 0 power-up. It also allows the pony to receive the power-up again... Why do you think I haven't used it on Twilight yet?