Originally Posted by militantpotato
For a thin layer, 3 days, for a thicker layer (like sealing) 7-10 days.
well even though it isn't "correct" I recently put the handle of a socket driver into the side of my ten gallon salt tank.
so I drained it down below the cracks and siliconed a patch in place and then let it sit for about 20 hours and filled it back up. it was a 4"x6" patch, so not a small dab of silicone for sure. LOL
The whole time my pseudochromis, coral shrimp and a hermy stayed in the tank and I/they have had absolutely no issues as a result.
This was an emergency situation though and I would not recommend it, but it does illustrate that after about 24 hours it is should be fine.
ps, I am also using Chemi-Pure in that tank so not sure how much of a difference that made.