I let mine air dry for 1 week. I filled my tank up and letting it soak in tap water for 2 weeks before I put my RO/DI water in it.
The finished cure time on my tube said 48 hours. It did not cure 100% in 48 hours. I siliconed my overflow and the 2 bulkhead in the overflow to the tank the same time I rewebbed the 180gallon. After about 2 weeks I noticed the the overflow was not 100% level so I took off, which took me about a hour since I basicly glued in on the tank. When I took that puppy off the silicone in the middle smelled as if I just applied it, even though it was hard. I'm gonna wait 3 weeks before I put any RO/DI in it, just to be on the safe side.
You would think after 2 or more weeks that silicon wouldn't have any smell but mine did.