Talk:Mana vortex
From The Heroes of Might and Magic III wiki
Be careful which hero you use to interact with your dungeon town at the start of each week, as you usually won't want a support hero doubling their mana instead of your main hero. If you have a hero garrisoned (ie: defender hero holding statue of legion pieces) you can strategically bypass the vortex doubling effect by navigating to your dungeon castle view through another town (using the right-side navigation pane).