Hello; Most tanks have leaked right away after a reseal if I botched the job. However, a few have started to leak after a few days. I like to leave a tank set up for at least a full day and will leave one longer when practical. A week is likely to be plenty. It often comes down to where the tank is to be set up. In a basement with a drain a leak is just a dissapointing thing. In a room with wood floors or carpet it can be come an expensive thing.
Also keep in mind that new leaks can start when a tank is moved so keep a close watch as it is being filled.
Some on this forum have suggested allowing the silicone to cure for several days before adding water, not just the 24 hours cited on the labels. I intend to go to a longer cure time in the future.