Ran across this note to myself from years ago (LOL) and thought I would share since so many ask how to sterilize a tank. I got the information from the one and only LFS I deal with. In all the years of dealing with them, they have never steered me wrong.
It is as easy as this - 1/2 cup of canning salt to a gal. of water. Run for 24 hours. You can us this on your gravel, decorations, nets, filter, etc. - not live plants, of course. They told me that any and all freshwater critters can't survive this treatment.
Once the 24 hours is up rinse everything extremely well - maybe a couple good rinses?
Hope this helps some of you that are looking for a safe alternative to using bleach to disinfect.