i'm getting a new (to me) tank tomorrow and the guy said it holds water fine with no leaks, but there are a couple knicks in the silicone from tank cleaning, and is going to throw in the silicone with it just to be safe. my question is, can i just goop this crap on over the existing seal or what? i've never done this, nor want to make a project as of it, so don't want to strip down and redo. and how long does it usually take to dry. i have my current tank sold but can't get rid of it till everythings transferred to the new one.. i'm that '1 tank' person