How Long ?

[fshfrk]

I would wait untill you can't smell anything. Maybe put a fan over the tank to speed the proccess.

[Jose]

After I posted thats what came to me. Hopefully smell starts going away tomorrow so I can start adding everything.

[nacra99]

Thin beads cure quicker. An overly thick blob may take days to fully cure.
For most aquarium sealing applications, I wait 24 hrs to 48 hrs depending how much i use and if i can still smell the acetic acid.
Unless the water is poorly buffered, then i would wait a week or so. Houston tapwater is usually buffered enough to able to handle the trace amounts of acetic acid produced after you can't smell it anymore.

Incidentally, i almost never ever use silicone sold for aquarium use. I've always used either GE 1 or DAP 100% silicone. Easily available at big box stores and usually half the price.