How long can a tank run without filtered water

[marie]

A few years ago, my return pump crapped out on me and I had to wait 2 days for a new one, I kept the water circulating in the sump with a couple of maxi-jet power heads and I had the tunze power heads in the display pointing more towards the surface for extra oxygen.

Everything came through with flying colours except I forgot that the overflows had no circulation for more then 48hrs and when I finally turned the return pump on, the worst rotten egg smell ever filled the house....nobody seemed to mind in the tank though and the corals never even withdrew their polyps