Ok, guys, I have been reading the arena event thread and there are people that have accumulated enough SoW to battle 500 times without refilling. How do you do that?

The only way I know to pile on SoW is by making low tier (1st and 2nd level) sacrifices and grinding dungeons. That usually gives me enough to go 50-60 battles in the gauntlet run. Besides that when there is no event I don't play more than 30-50 battles in the arena a week. Eventually I end up buying refills.

Any tips would be appreciated.