cracked glass

Hello! The underside of the tank cracked (about 1 inch, there’s 2 ways I can think of to fix this and I just wondering what is better? 1. Glued the crack with a new piece of glass pane or 2. Just glued it with sealant Any thoughts?

So I just bought a second-hand 55 gallon aquarium with a stand and the guy I bought them from threw in a 30 gallon he wasn't using for free. The 55 looks fine, crossbar and silicone all intact. The 30 gallon however has a small chip in one of the glass faces, it appears to be about 1/16" deep...