Quote Originally Posted by Polkster13
I would not do it. If you do decide to reseal the tank, you should really redo all of the seals. This means scraping off the old silicone from all of the joints and applying all new silicone. You will get mixed results if you try to apply new silicone over old silicone. It is not recommended! I have seen it done and sometimes it will hold, but a lot of times it doesn't. Also, you will get a different coloration between the two and the joint will be very noticable. This may or may not be a concern for you.
I'd have to second this advice.