All of you people that are using Thunder III in your rotation, stop using it and follow the rotation I posted above. You will find your damage phases are longer, and your regen phases are faster, smoother, and allow for boss issues (Ifrit doing his charge where you cannot target him, ect)

Thunder III cost DOUBLE the mana nearly DOUBLE the cast time, and only adds THIRTY potency. The Thunder Storm proc does add 100 potency, but it's a 5% chance, it's simply not worth sacrificing 1 Fire cast per damage phase.