QUOTE(MiAla @ Sep 8 2011, 19:21)

Currently I am @ 20,7 Mana regen, with Quintstar aura applied.
I assume that equals 1,38 mp/turn for me in battle.
How much profit I'd possibly receive from Rainbow aura?
Providing that they both work from base, and that they both give +50%, that means your base should be 13,8 regen.
So adding rainbow aura should up your total regen to 27,6, or 1,84 mp/turn.
Unless they work multiplicatively, in which case you would get 225% of your base, so 2,07 mp/turn.