Talk:Perpetual Vortex/@comment-174.54.100.25-20150416002002/@comment-25506106-20150416221059

the mod says 'based on maximum duration'. each time you add one, the max duration increases, so they become more and more efficent with each one added. After throwing a few, tossing a single vortex in can increase the duration by several minutes.

Then again, with a high efficency build, cost of vortex never been that great an issue, but with these it might be worth it to not bother with full efficency